fix: upgrade multiple dependencies with Snyk (#406)

Snyk has created this PR to upgrade:
  - @babel/core from 7.6.4 to 7.8.6.
    See this package in NPM: https://www.npmjs.com/package/@babel/core
  - @babel/preset-env from 7.6.3 to 7.8.6.
    See this package in NPM: https://www.npmjs.com/package/@babel/preset-env

See this project in Snyk:
https://app.snyk.io/org/nodeshift-agg/project/0569fa2f-39b2-4a6a-9bdc-8ac878d28a88?utm_source=github&utm_medium=upgrade-pr

package.json

@@ -50,8 +50,8 @@
   },
   "homepage": "https://nodeshift.dev/opossum",
   "devDependencies": {
-    "@babel/core": "^7.6.4",
-    "@babel/preset-env": "^7.6.3",
+    "@babel/core": "^7.8.6",
+    "@babel/preset-env": "^7.8.6",
     "babel-loader": "^8.0.6",
     "codacy-coverage": "^3.4.0",
     "coveralls": "^3.0.3",