chore(package): update extract-text-webpack-plugin to version 2.1.2

Closes #16

Author: greenkeeper[bot]

package.json

@@ -27,7 +27,7 @@
     "awesome-typescript-loader": "^3.1.2",
     "cross-env": "4.0.0",
     "enzyme": "^2.8.2",
-    "extract-text-webpack-plugin": "2.1.0",
+    "extract-text-webpack-plugin": "2.1.2",
     "html-webpack-plugin": "2.28.0",
     "jest": "^19.0.2",
     "karma": "^1.6.0",