fix: upgrade css-loader from 3.0.0 to 3.4.2

Snyk has created this PR to upgrade css-loader from 3.0.0 to 3.4.2.

See this package in NPM:
https://www.npmjs.com/package/css-loader

See this project in Snyk:
https://app.snyk.io/org/luisalejandro/project/b71a9271-9b95-498b-8074-fe63f95f575d?utm_source=github&utm_medium=upgrade-pr

package.json

@@ -44,7 +44,7 @@
     "concurrently": "5.0.1",
     "copy-webpack-plugin": "5.0.5",
     "cross-env": "7.0.2",
-    "css-loader": "3.0.0",
+    "css-loader": "3.4.2",
     "css-mqpacker": "7.0.0",
     "cssnano": "4.1.10",
     "eslint": "6.2.0",