chore(deps): update dependency postcss-loader to v7

Author: renovate[bot]

package.json

@@ -142,7 +142,7 @@
     "jest": "^26.6.3",
     "nock": "^13.0.5",
     "postcss": "^8.4.30",
-    "postcss-loader": "^4.1.0",
+    "postcss-loader": "^7.0.0",
     "prettier": "^2.8.8",
     "react-test-renderer": "=16.14.0",
     "style-loader": "^3.3.3",