Merge pull request #1642 from mozilla/greenkeeper/babel-core-6.22.1

Update babel-core to the latest version 🚀

package.json

@@ -195,7 +195,7 @@
   },
   "devDependencies": {
     "autoprefixer": "6.6.1",
-    "babel-core": "6.21.0",
+    "babel-core": "6.22.1",
     "babel-eslint": "7.1.0",
     "babel-gettext-extractor": "git+https://github.com/muffinresearch/babel-gettext-extractor.git#ecd85dea4553247a3cb579da817df29f381df5b9",
     "babel-loader": "6.2.10",