Bump shivammathur/setup-php from 2.11.0 to 2.15.0

Bumps [shivammathur/setup-php](https://github.com/shivammathur/setup-php) from 2.11.0 to 2.15.0.
- [Release notes](https://github.com/shivammathur/setup-php/releases)
- [Commits](shivammathur/setup-php@2.11.0...2.15.0)

---
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]

.github/workflows/test.yaml

@@ -25,7 +25,7 @@ jobs:
               uses: actions/checkout@v2
 
             - name: php
-              uses: shivammathur/setup-php@2.11.0
+              uses: shivammathur/setup-php@2.15.0
               with:
                   php-version: ${{ matrix.php-version }}