Bump actions/checkout from 5 to 6

Bumps [actions/checkout](https://github.com/actions/checkout) from 5 to 6.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v5...v6)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

.github/workflows/build.yml

@@ -7,7 +7,7 @@ jobs:
       matrix:
         ruby: ['2.4', '2.5', '2.6', '2.7', '3.0', '3.1', '3.2', '3.3']
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: ruby/setup-ruby@v1
         with:
           ruby-version: ${{ matrix.ruby }}

.github/workflows/codeql-analysis.yml

@@ -38,7 +38,7 @@ jobs:
 
     steps:
     - name: Checkout repository
-      uses: actions/checkout@v5
+      uses: actions/checkout@v6
 
     # Initializes the CodeQL tools for scanning.
     - name: Initialize CodeQL