Update @babel/core requirement from 7.3.4 to 7.4.0

Updates the requirements on [@babel/core](https://github.com/babel/babel) to permit the latest version.
- [Release notes](https://github.com/babel/babel/releases)
- [Changelog](https://github.com/babel/babel/blob/master/CHANGELOG.md)
- [Commits](babel/babel@v7.3.4...v7.4.0)

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

Author: dependabot-support

package.json

@@ -34,7 +34,7 @@
   },
   "devDependencies": {
     "@babel/cli": "7.2.3",
-    "@babel/core": "7.3.4",
+    "@babel/core": "7.4.0",
     "@babel/plugin-syntax-dynamic-import": "7.2.0",
     "@babel/preset-env": "7.3.4",
     "@babel/preset-react": "7.0.0",