Bump actions/checkout from 2 to 3.1.0 (#2)

Bumps [actions/checkout](https://github.com/actions/checkout) from 2 to 3.1.0.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v2...v3.1.0)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-type: direct:production
  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>

.github/workflows/run-tests.yml

@@ -11,7 +11,7 @@ jobs:
                 php: [8.0]
                 dependency-version: [highest, lowest]
         steps:
-            - uses: actions/checkout@v2
+            - uses: actions/checkout@v3
 
             - name: Configure PHP
               uses: shivammathur/setup-php@v2