Bump shivammathur/setup-php from 2.13.0 to 2.16.0 (#28)

Bumps [shivammathur/setup-php](https://github.com/shivammathur/setup-php) from 2.13.0 to 2.16.0.
- [Release notes](https://github.com/shivammathur/setup-php/releases)
- [Commits](shivammathur/setup-php@2.13.0...2.16.0)

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

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

Author: dependabot[bot]

.github/workflows/run-tests.yml

@@ -19,7 +19,7 @@ jobs:
               uses: actions/checkout@v2.4.0
 
             - name: Setup PHP
-              uses: shivammathur/setup-php@2.13.0
+              uses: shivammathur/setup-php@2.16.0
               with:
                   php-version: ${{ matrix.php }}
                   extensions: mbstring, fileinfo