fix(package): update babel-core to version 6.26.0

Closes #27

Author: greenkeeper[bot]

package.json

@@ -25,7 +25,7 @@
     "node": ">=0.12.0"
   },
   "dependencies": {
-    "babel-core": "~6.18.2",
+    "babel-core": "~6.26.0",
     "babel-loader": "6.2.7",
     "babel-preset-react-hmre": "^1.1.1",
     "babel-plugin-react-transform": "2.0.2",