build(deps): bump postcss-selector-parser from 6.0.12 to 6.0.13 (#823)

Bumps [postcss-selector-parser](https://github.com/postcss/postcss-selector-parser) from 6.0.12 to 6.0.13.
- [Release notes](https://github.com/postcss/postcss-selector-parser/releases)
- [Changelog](https://github.com/postcss/postcss-selector-parser/blob/master/CHANGELOG.md)
- [Commits](postcss/postcss-selector-parser@v6.0.12...v6.0.13)

---
updated-dependencies:
- dependency-name: postcss-selector-parser
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

package.json

@@ -12,7 +12,7 @@
   "dependencies": {
     "postcss-media-query-parser": "^0.2.3",
     "postcss-resolve-nested-selector": "^0.1.1",
-    "postcss-selector-parser": "^6.0.12",
+    "postcss-selector-parser": "^6.0.13",
     "postcss-value-parser": "^4.2.0"
   },
   "devDependencies": {