Update babel7 to the latest version 🚀 (#1337)

* chore(package): update @babel/core to version 7.6.4

* chore(package): update lockfile package-lock.json

Author: greenkeeper[bot]

package-lock.json

@@ -71,7 +71,7 @@
     "semver": "^6.3.0"
   },
   "devDependencies": {
-    "@babel/core": "7.6.3",
+    "@babel/core": "7.6.4",
     "@babel/plugin-proposal-decorators": "7.6.0",
     "@babel/plugin-transform-regenerator": "7.4.5",
     "@babel/plugin-transform-runtime": "7.6.2",