build(deps-dev): bump postcss-loader from 6.2.1 to 8.2.0 (#1558)

Bumps [postcss-loader](https://github.com/webpack-contrib/postcss-loader) from 6.2.1 to 8.2.0.
- [Release notes](https://github.com/webpack-contrib/postcss-loader/releases)
- [Changelog](https://github.com/webpack/postcss-loader/blob/main/CHANGELOG.md)
- [Commits](webpack/postcss-loader@v6.2.1...v8.2.0)

---
updated-dependencies:
- dependency-name: postcss-loader
  dependency-version: 8.2.0
  dependency-type: direct:development
  update-type: version-update:semver-major
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

package-lock.json

@@ -359,7 +359,7 @@
     "css-loader": "^7.1.2",
     "file-loader": "^6.2.0",
     "postcss": "^8.4.31",
-    "postcss-loader": "^6.2.1",
+    "postcss-loader": "^8.2.0",
     "process": "0.11.10",
     "sass": "^1.55.0",
     "sass-loader": "^12.6.0",