Bumped style-loader to v1.0.0. Aligned the webpack config to the new loader API.

package.json

@@ -54,7 +54,7 @@
     "lint-staged": "^7.0.0",
     "postcss-loader": "^3.0.0",
     "raw-loader": "^1.0.0",
-    "style-loader": "^0.23.0",
+    "style-loader": "^1.0.0",
     "uglifyjs-webpack-plugin": "^1.2.7",
     "webpack": "^4.15.0",
     "webpack-cli": "^3.0.8"

webpack.config.js

@@ -68,7 +68,7 @@ module.exports = {
 					{
 						loader: 'style-loader',
 						options: {
-							singleton: true
+							injectType: 'singletonStyleTag'
 						}
 					},
 					{