diff --git a/src/Config.js b/src/Config.js
index 487061b..c1a0558 100644
--- a/src/Config.js
+++ b/src/Config.js
@@ -134,7 +134,10 @@ module.exports = class extends ChainedMap {
   }
 
   toString(options) {
-    return module.exports.toString(this.toConfig(), options);
+    return module.exports.toString(
+      this.toConfig(),
+      options
+    );
   }
 
   merge(obj = {}, omit = []) {
diff --git a/yarn.lock b/yarn.lock
index 402c982..c963b7a 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -270,8 +270,8 @@ aproba@^1.0.3, aproba@^1.1.1:
   resolved "https://registry.yarnpkg.com/aproba/-/aproba-1.2.0.tgz#6802e6264efd18c790a1b0d517f0f2627bf2c94a"
 
 are-we-there-yet@~1.1.2:
-  version "1.1.4"
-  resolved "https://registry.yarnpkg.com/are-we-there-yet/-/are-we-there-yet-1.1.4.tgz#bb5dca382bb94f05e15194373d16fd3ba1ca110d"
+  version "1.1.5"
+  resolved "https://registry.yarnpkg.com/are-we-there-yet/-/are-we-there-yet-1.1.5.tgz#4b35c2944f062a8bfcda66410760350fe9ddfc21"
   dependencies:
     delegates "^1.0.0"
     readable-stream "^2.0.6"
@@ -1348,8 +1348,8 @@ core-assert@^0.2.0:
     is-error "^2.2.0"
 
 core-js@^2.0.0, core-js@^2.4.0, core-js@^2.5.0:
-  version "2.5.6"
-  resolved "https://registry.yarnpkg.com/core-js/-/core-js-2.5.6.tgz#0fe6d45bf3cac3ac364a9d72de7576f4eb221b9d"
+  version "2.5.7"
+  resolved "https://registry.yarnpkg.com/core-js/-/core-js-2.5.7.tgz#f972608ff0cead68b841a16a932d0b183791814e"
 
 core-util-is@1.0.2, core-util-is@~1.0.0:
   version "1.0.2"
@@ -1477,9 +1477,9 @@ deep-equal@^1.0.0:
   version "1.0.1"
   resolved "https://registry.yarnpkg.com/deep-equal/-/deep-equal-1.0.1.tgz#f5d260292b660e084eff4cdbc9f08ad3247448b5"
 
-deep-extend@^0.5.1:
-  version "0.5.1"
-  resolved "https://registry.yarnpkg.com/deep-extend/-/deep-extend-0.5.1.tgz#b894a9dd90d3023fbf1c55a394fb858eb2066f1f"
+deep-extend@^0.6.0:
+  version "0.6.0"
+  resolved "https://registry.yarnpkg.com/deep-extend/-/deep-extend-0.6.0.tgz#c4fa7c95404a17a9c3e8ca7e1537312b736330ac"
 
 deep-is@~0.1.3:
   version "0.1.3"
@@ -2807,7 +2807,7 @@ jsesc@~0.5.0:
   version "0.5.0"
   resolved "https://registry.yarnpkg.com/jsesc/-/jsesc-0.5.0.tgz#e7dee66e35d6fc16f710fe91d5cf69f70f08911d"
 
-json-parse-better-errors@^1.0.1:
+json-parse-better-errors@^1.0.1, json-parse-better-errors@^1.0.2:
   version "1.0.2"
   resolved "https://registry.yarnpkg.com/json-parse-better-errors/-/json-parse-better-errors-1.0.2.tgz#bb867cfb3450e69107c131d1c514bab3dc8bcaa9"
 
@@ -3019,8 +3019,8 @@ map-visit@^1.0.0:
     object-visit "^1.0.0"
 
 matcher@^1.0.0:
-  version "1.1.0"
-  resolved "https://registry.yarnpkg.com/matcher/-/matcher-1.1.0.tgz#4ad3a9cb6585186dc95cb8a08c7de936caed17ee"
+  version "1.1.1"
+  resolved "https://registry.yarnpkg.com/matcher/-/matcher-1.1.1.tgz#51d8301e138f840982b338b116bb0c09af62c1c2"
   dependencies:
     escape-string-regexp "^1.0.4"
 
@@ -3152,11 +3152,11 @@ minimist@^1.1.3, minimist@^1.2.0:
   version "1.2.0"
   resolved "https://registry.yarnpkg.com/minimist/-/minimist-1.2.0.tgz#a35008b20f41383eec1fb914f4cd5df79a264284"
 
-minipass@^2.2.1, minipass@^2.2.4:
-  version "2.3.1"
-  resolved "https://registry.yarnpkg.com/minipass/-/minipass-2.3.1.tgz#4e872b959131a672837ab3cb554962bc84b1537d"
+minipass@^2.2.1, minipass@^2.3.3:
+  version "2.3.3"
+  resolved "https://registry.yarnpkg.com/minipass/-/minipass-2.3.3.tgz#a7dcc8b7b833f5d368759cce544dccb55f50f233"
   dependencies:
-    safe-buffer "^5.1.1"
+    safe-buffer "^5.1.2"
     yallist "^3.0.0"
 
 minizlib@^1.1.0:
@@ -3664,7 +3664,7 @@ pkg-up@^2.0.0:
   dependencies:
     find-up "^2.1.0"
 
-plur@^2.0.0, plur@^2.1.2:
+plur@^2.0.0:
   version "2.1.2"
   resolved "https://registry.yarnpkg.com/plur/-/plur-2.1.2.tgz#7482452c1a0f508e3e344eaec312c91c29dc655a"
   dependencies:
@@ -3691,8 +3691,8 @@ preserve@^0.2.0:
   resolved "https://registry.yarnpkg.com/preserve/-/preserve-0.2.0.tgz#815ed1f6ebc65926f865b310c0713bcb3315ce4b"
 
 prettier@^1.12.1:
-  version "1.12.1"
-  resolved "https://registry.yarnpkg.com/prettier/-/prettier-1.12.1.tgz#c1ad20e803e7749faf905a409d2367e06bbe7325"
+  version "1.13.0"
+  resolved "https://registry.yarnpkg.com/prettier/-/prettier-1.13.0.tgz#054de8d5fb1a4405c845d16183f58a2c301f6f16"
 
 pretty-ms@^0.2.1:
   version "0.2.2"
@@ -3701,11 +3701,10 @@ pretty-ms@^0.2.1:
     parse-ms "^0.1.0"
 
 pretty-ms@^3.0.0:
-  version "3.1.0"
-  resolved "https://registry.yarnpkg.com/pretty-ms/-/pretty-ms-3.1.0.tgz#e9cac9c76bf6ee52fe942dd9c6c4213153b12881"
+  version "3.2.0"
+  resolved "https://registry.yarnpkg.com/pretty-ms/-/pretty-ms-3.2.0.tgz#87a8feaf27fc18414d75441467d411d6e6098a25"
   dependencies:
     parse-ms "^1.0.0"
-    plur "^2.1.2"
 
 private@^0.1.8:
   version "0.1.8"
@@ -3769,8 +3768,8 @@ punycode@^1.2.4, punycode@^1.4.1:
   resolved "https://registry.yarnpkg.com/punycode/-/punycode-1.4.1.tgz#c0d5a63b2718800ad8e1eb0fa5269c84dd41845e"
 
 punycode@^2.1.0:
-  version "2.1.0"
-  resolved "https://registry.yarnpkg.com/punycode/-/punycode-2.1.0.tgz#5f863edc89b96db09074bad7947bf09056ca4e7d"
+  version "2.1.1"
+  resolved "https://registry.yarnpkg.com/punycode/-/punycode-2.1.1.tgz#b58b010ac40c22c5657616c8d2c2c02c7bf479ec"
 
 q@1.5.1:
   version "1.5.1"
@@ -3810,10 +3809,10 @@ randomfill@^1.0.3:
     safe-buffer "^5.1.0"
 
 rc@^1.0.1, rc@^1.1.6, rc@^1.1.7:
-  version "1.2.7"
-  resolved "https://registry.yarnpkg.com/rc/-/rc-1.2.7.tgz#8a10ca30d588d00464360372b890d06dacd02297"
+  version "1.2.8"
+  resolved "https://registry.yarnpkg.com/rc/-/rc-1.2.8.tgz#cd924bf5200a075b83c188cd6b9e211b7fc0d3ed"
   dependencies:
-    deep-extend "^0.5.1"
+    deep-extend "^0.6.0"
     ini "~1.3.0"
     minimist "^1.2.0"
     strip-json-comments "~2.0.1"
@@ -4341,7 +4340,7 @@ stream-shift@^1.0.0:
   version "1.0.0"
   resolved "https://registry.yarnpkg.com/stream-shift/-/stream-shift-1.0.0.tgz#d5c752825e5367e786f78e18e445ea223a155952"
 
-string-width@^1.0.1, string-width@^1.0.2:
+string-width@^1.0.1:
   version "1.0.2"
   resolved "https://registry.yarnpkg.com/string-width/-/string-width-1.0.2.tgz#118bdf5b8cdc51a2a7e70d211e07e2b0b9b107d3"
   dependencies:
@@ -4349,7 +4348,7 @@ string-width@^1.0.1, string-width@^1.0.2:
     is-fullwidth-code-point "^1.0.0"
     strip-ansi "^3.0.0"
 
-string-width@^2.0.0, string-width@^2.1.0, string-width@^2.1.1:
+"string-width@^1.0.2 || 2", string-width@^2.0.0, string-width@^2.1.0, string-width@^2.1.1:
   version "2.1.1"
   resolved "https://registry.yarnpkg.com/string-width/-/string-width-2.1.1.tgz#ab93f27a8dc13d28cac815c462143a6d9012ae9e"
   dependencies:
@@ -4462,12 +4461,12 @@ tapable@^1.0.0:
   resolved "https://registry.yarnpkg.com/tapable/-/tapable-1.0.0.tgz#cbb639d9002eed9c6b5975eb20598d7936f1f9f2"
 
 tar@^4:
-  version "4.4.2"
-  resolved "https://registry.yarnpkg.com/tar/-/tar-4.4.2.tgz#60685211ba46b38847b1ae7ee1a24d744a2cd462"
+  version "4.4.4"
+  resolved "https://registry.yarnpkg.com/tar/-/tar-4.4.4.tgz#ec8409fae9f665a4355cc3b4087d0820232bb8cd"
   dependencies:
     chownr "^1.0.1"
     fs-minipass "^1.2.5"
-    minipass "^2.2.4"
+    minipass "^2.3.3"
     minizlib "^1.1.0"
     mkdirp "^0.5.0"
     safe-buffer "^5.1.2"
@@ -4676,8 +4675,8 @@ update-notifier@^2.3.0:
     xdg-basedir "^3.0.0"
 
 uri-js@^4.2.1:
-  version "4.2.1"
-  resolved "https://registry.yarnpkg.com/uri-js/-/uri-js-4.2.1.tgz#4595a80a51f356164e22970df64c7abd6ade9850"
+  version "4.2.2"
+  resolved "https://registry.yarnpkg.com/uri-js/-/uri-js-4.2.2.tgz#94c540e1ff772956e2299507c010aea6c8838eb0"
   dependencies:
     punycode "^2.1.0"
 
@@ -4765,8 +4764,8 @@ webpack-sources@^1.0.1, webpack-sources@^1.1.0:
     source-map "~0.6.1"
 
 webpack@^4.5.0:
-  version "4.8.3"
-  resolved "https://registry.yarnpkg.com/webpack/-/webpack-4.8.3.tgz#957c8e80000f9e5cc03d775e78b472d8954f4eeb"
+  version "4.9.1"
+  resolved "https://registry.yarnpkg.com/webpack/-/webpack-4.9.1.tgz#fa7bd738b17fd7f09f37da461b2f5c16c6565f34"
   dependencies:
     "@webassemblyjs/ast" "1.4.3"
     "@webassemblyjs/wasm-edit" "1.4.3"
@@ -4778,6 +4777,7 @@ webpack@^4.5.0:
     chrome-trace-event "^0.1.1"
     enhanced-resolve "^4.0.0"
     eslint-scope "^3.7.1"
+    json-parse-better-errors "^1.0.2"
     loader-runner "^2.3.0"
     loader-utils "^1.1.0"
     memory-fs "~0.4.1"
@@ -4796,16 +4796,16 @@ well-known-symbols@^1.0.0:
   resolved "https://registry.yarnpkg.com/well-known-symbols/-/well-known-symbols-1.0.0.tgz#73c78ae81a7726a8fa598e2880801c8b16225518"
 
 which@^1.2.9:
-  version "1.3.0"
-  resolved "https://registry.yarnpkg.com/which/-/which-1.3.0.tgz#ff04bdfc010ee547d780bec38e1ac1c2777d253a"
+  version "1.3.1"
+  resolved "https://registry.yarnpkg.com/which/-/which-1.3.1.tgz#a45043d54f5805316da8d62f9f50918d3da70b0a"
   dependencies:
     isexe "^2.0.0"
 
 wide-align@^1.1.0:
-  version "1.1.2"
-  resolved "https://registry.yarnpkg.com/wide-align/-/wide-align-1.1.2.tgz#571e0f1b0604636ebc0dfc21b0339bbe31341710"
+  version "1.1.3"
+  resolved "https://registry.yarnpkg.com/wide-align/-/wide-align-1.1.3.tgz#ae074e6bdc0c14a431e804e624549c633b000457"
   dependencies:
-    string-width "^1.0.2"
+    string-width "^1.0.2 || 2"
 
 widest-line@^2.0.0:
   version "2.0.0"