chore(deps-dev): bump postcss-loader from 5.0.0 to 5.2.0

Bumps [postcss-loader](https://github.com/webpack-contrib/postcss-loader) from 5.0.0 to 5.2.0.
- [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@v5.0.0...v5.2.0)

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

Author: dependabot[bot]

package-lock.json

@@ -52,7 +52,7 @@
     "gh-pages": "^3.1.0",
     "husky": "^4.3.8",
     "lint-staged": "^10.5.3",
-    "postcss-loader": "^5.0.0",
+    "postcss-loader": "^5.2.0",
     "sass": "^1.32.5",
     "sass-loader": "^11.0.1",
     "style-loader": "^2.0.0",