GH Actions: Bump actions/checkout from 4 to 5

Bumps [actions/checkout](https://github.com/actions/checkout) from 4 to 5.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v4...v5)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-version: '5'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

.github/workflows/continuous-integration.yml

@@ -32,7 +32,7 @@ jobs:
             experimental: true
             composer-options: "--ignore-platform-reqs"
     steps:
-      - uses: "actions/checkout@v4"
+      - uses: "actions/checkout@v5"
       - uses: "shivammathur/setup-php@v2"
         with:
           php-version: "${{ matrix.php-version }}"
@@ -48,7 +48,7 @@ jobs:
     name: "Static Analysis"
     runs-on: "ubuntu-latest"
     steps:
-      - uses: "actions/checkout@v4"
+      - uses: "actions/checkout@v5"
       - uses: "shivammathur/setup-php@v2"
         with:
           php-version: "8.2"