github-actions(deps): bump actions/checkout from 6 to 7

Bumps [actions/checkout](https://github.com/actions/checkout) from 6 to 7.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v6...v7)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-version: '7'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

.github/workflows/diagnostics.yml

@@ -34,7 +34,7 @@ jobs:
 
     steps:
       - name: Pull source
-        uses: actions/checkout@v6
+        uses: actions/checkout@v7
 
       - name: Setup PHP with PECL extension
         uses: shivammathur/setup-php@v2