chore(package): update babel-loader to version 8.0.4

Closes #50

Author: greenkeeper[bot]

package.json

@@ -32,7 +32,7 @@
   },
   "devDependencies": {
     "babel-core": "^6.26.0",
-    "babel-loader": "^7.1.2",
+    "babel-loader": "^8.0.4",
     "babel-minify-webpack-plugin": "^0.3.0",
     "babel-plugin-transform-runtime": "^6.23.0",
     "babel-preset-env": "^1.6.0",