Bump @babel/core from 7.2.0 to 7.4.4 in /webpack

Bumps [@babel/core](https://github.com/babel/babel) from 7.2.0 to 7.4.4.
- [Release notes](https://github.com/babel/babel/releases)
- [Changelog](https://github.com/babel/babel/blob/master/CHANGELOG.md)
- [Commits](babel/babel@v7.2.0...v7.4.4)

Signed-off-by: dependabot[bot] <support@dependabot.com>

Author: dependabot-support

webpack/package-lock.json

@@ -10,7 +10,7 @@
     "turbolinks": "^5.2.0"
   },
   "devDependencies": {
-    "@babel/core": "^7.2.0",
+    "@babel/core": "^7.4.4",
     "@babel/plugin-proposal-class-properties": "^7.4.4",
     "@babel/preset-env": "^7.2.0",
     "babel-loader": "^8.0.4",