Bump postcss-import from 14.1.0 to 15.0.0 (#6323)

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](postcss/postcss-import@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>

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

package.json

@@ -183,7 +183,7 @@
     "npm-run-all": "^4.1.5",
     "patch-package": "^6.5.0",
     "postcss-html": "^1.5.0",
-    "postcss-import": "^14.1.0",
+    "postcss-import": "^15.0.0",
     "postcss-less": "^6.0.0",
     "postcss-sass": "^0.5.0",
     "postcss-scss": "^4.0.5",