Upgraded version of ESLint.

package.json

@@ -45,9 +45,9 @@
     "@ckeditor/ckeditor5-theme-lark": "^11.0.0",
     "@ckeditor/ckeditor5-upload": "^10.0.2",
     "@ckeditor/ckeditor5-table": "^10.1.0",
-    "postcss-loader": "^2.1.5",
+    "postcss-loader": "^3.0.0",
     "raw-loader": "^0.5.1",
-    "style-loader": "^0.21.0",
+    "style-loader": "^0.23.0",
     "uglifyjs-webpack-plugin": "^1.2.7",
     "webpack": "^4.15.0",
     "webpack-cli": "^3.0.8"