Bump shivammathur/setup-php from 2.20.1 to 2.21.0

Bumps [shivammathur/setup-php](https://github.com/shivammathur/setup-php) from 2.20.1 to 2.21.0.
- [Release notes](https://github.com/shivammathur/setup-php/releases)
- [Commits](shivammathur/setup-php@2.20.1...2.21.0)

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

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

Author: dependabot[bot]

action.yml

@@ -47,7 +47,7 @@ runs:
       shell: bash
 
     - name: Installing PHP...
-      uses: shivammathur/setup-php@2.20.1
+      uses: shivammathur/setup-php@2.21.0
       with:
         php-version: ${{ env.NEEDED_PHP_VERSION }}
         extensions: curl, gd, pdo_mysql, json, mbstring, pcre, session