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

Author: greenkeeper[bot]

package.json

@@ -29,7 +29,7 @@
     "clean-webpack-plugin": "3.0.0",
     "copy-webpack-plugin": "5.1.1",
     "cross-env": "6.0.3",
-    "css-loader": "3.3.2",
+    "css-loader": "3.4.0",
     "file-loader": "5.0.2",
     "mini-css-extract-plugin": "0.8.1",
     "postcss-loader": "3.0.0",