Bump postcss-import from 14.1.0 to 15.0.0

Bumps [postcss-import](https://github.com/postcss/postcss-import) from 14.1.0 to 15.0.0.
- [Release notes](https://github.com/postcss/postcss-import/releases)
- [Changelog](https://github.com/postcss/postcss-import/blob/master/CHANGELOG.md)
- [Commits](https://github.com/postcss/postcss-import/compare/14.1.0...15.0.0)

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

Signed-off-by: dependabot[bot] <support@github.com>

package.json

@@ -23,7 +23,7 @@
         "postcss": "^8.4.16",
         "postcss-combine-duplicated-selectors": "^10.0.2",
         "postcss-combine-media-query": "^1.0.1",
-        "postcss-import": "^14.0.0",
+        "postcss-import": "^15.0.0",
         "postcss-loader": "^7.0.1",
         "stylelint": "^14.11.0",
         "stylelint-config-standard": "^28.0.0",