Update babel-runtime version (#208)

package.json

@@ -41,7 +41,7 @@
     "babel-preset-es2015": "^6.1.18",
     "babel-preset-es2015-rollup": "^1.1.1",
     "babel-preset-stage-2": "^6.1.18",
-    "babel-runtime": "^5.8.0",
+    "babel-runtime": "^6.0.0",
     "casperjs": "^1.1.0-beta5",
     "chai": "^3.4.1",
     "css-loader": "^0.23.1",