chore(deps): update dependency webpack to ^4.39.0 (#450)

Author: renovate[bot]

package-lock.json

@@ -62,7 +62,7 @@
     "prettier": "^1.18.2",
     "standard-version": "^7.0.0",
     "supertest": "^4.0.2",
-    "webpack": "^4.38.0"
+    "webpack": "^4.39.0"
   },
   "keywords": [
     "webpack",