Update dependency css-loader to v7 (#10)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

package-lock.json

@@ -20,7 +20,7 @@
     "@babel/preset-env": "^7.9.6",
     "@types/mark.js": "^8.11.12",
     "babel-preset-minify": "^0.5.1",
-    "css-loader": "^6.5.1",
+    "css-loader": "^7.0.0",
     "css-minimizer-webpack-plugin": "^8.0.0",
     "mini-css-extract-plugin": "^2.4.5",
     "terser-webpack-plugin": "^5.2.5",