fix(deps): update dependency css-loader to v7

Author: renovate[bot]

package-lock.json

@@ -9,7 +9,7 @@
     "ansi-regex": "6.0.1",
     "bootstrap-sass": "3.4.3",
     "bower": "1.8.12",
-    "css-loader": "6.11.0",
+    "css-loader": "7.1.1",
     "datatables.net": "1.13.11",
     "datatables.net-bs": "1.13.11",
     "mini-css-extract-plugin": "2.8.1",