chore(package): update css-loader to version 3.4.0

Closes #33

Author: greenkeeper[bot]

package.json

@@ -47,7 +47,7 @@
     "babel-plugin-styled-components": "^1.10.0",
     "coveralls": "^3.0.2",
     "cross-env": "^5.2.0",
-    "css-loader": "^2.0.0",
+    "css-loader": "^3.4.0",
     "enzyme": "^3.7.0",
     "enzyme-adapter-react-16": "^1.6.0",
     "eslint": "^5.6.1",