Bump shivammathur/setup-php from 2.21.0 to 2.28.0

Bumps [shivammathur/setup-php](https://github.com/shivammathur/setup-php) from 2.21.0 to 2.28.0.
- [Release notes](https://github.com/shivammathur/setup-php/releases)
- [Commits](shivammathur/setup-php@2.21.0...2.28.0)

---
updated-dependencies:
- dependency-name: shivammathur/setup-php
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

.github/workflows/ci.yml

@@ -38,7 +38,7 @@ jobs:
       - uses: actions/checkout@v3.0.2
 
       - name: Setup PHP
-        uses: shivammathur/setup-php@2.21.0
+        uses: shivammathur/setup-php@2.28.0
         with:
           php-version: ${{ matrix.php }}
           extensions: dom, curl, libxml, mbstring, zip, pcntl, pdo, sqlite, pdo_sqlite, bcmath, soap, intl, gd, exif, iconv