Merge pull request #575 from parity-js/dependabot/npm_and_yarn/babel/core-7.6.4

Author: dependabot-preview[bot]

package-lock.json

@@ -55,7 +55,7 @@
   },
   "devDependencies": {
     "@babel/cli": "^7.4.4",
-    "@babel/core": "^7.6.2",
+    "@babel/core": "^7.6.4",
     "@babel/node": "^7.5.5",
     "@babel/plugin-proposal-class-properties": "^7.5.5",
     "@babel/plugin-proposal-decorators": "^7.6.0",