chore(package): update @types/node to version 12.6.6

Closes #115

Author: greenkeeper[bot]

package.json

@@ -41,7 +41,7 @@
     "@types/chai": "^4",
     "@types/glob": "^7.1.1",
     "@types/mocha": "^5",
-    "@types/node": "~12.0.0",
+    "@types/node": "~12.6.6",
     "@types/yargs": "^13.0.0",
     "chai": "^4",
     "conventional-changelog-cli": "^2.0.21",