chore(deps): bump postcss-loader from 6.2.1 to 7.0.0

Bumps [postcss-loader](https://github.com/webpack-contrib/postcss-loader) from 6.2.1 to 7.0.0.
- [Release notes](https://github.com/webpack-contrib/postcss-loader/releases)
- [Changelog](https://github.com/webpack-contrib/postcss-loader/blob/master/CHANGELOG.md)
- [Commits](webpack-contrib/postcss-loader@v6.2.1...v7.0.0)

---
updated-dependencies:
- dependency-name: postcss-loader
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

package.json

@@ -70,7 +70,7 @@
     "optimize-css-assets-webpack-plugin": "^6.0.1",
     "postcss": "^8.4.14",
     "postcss-flexbugs-fixes": "^5.0.2",
-    "postcss-loader": "^6.2.1",
+    "postcss-loader": "^7.0.0",
     "postcss-normalize": "^10.0.1",
     "postcss-preset-env": "^7.7.2",
     "postcss-safe-parser": "^6.0.0",