Bump actions/checkout from 3 to 6 (#3170)

Bumps [actions/checkout](https://github.com/actions/checkout) from 3 to 6.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v3...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] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

.github/workflows/codeql.yml

@@ -20,7 +20,7 @@ jobs:
 
     steps:
     - name: Checkout repository
-      uses: actions/checkout@v4
+      uses: actions/checkout@v6
 
     # Initializes the CodeQL tools for scanning.
     - name: Initialize CodeQL

.github/workflows/ruby.yml

@@ -21,7 +21,7 @@ jobs:
     name: RuboCop
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v6
       - uses: ruby/setup-ruby@v1
         with:
           ruby-version: '3.4'
@@ -47,7 +47,7 @@ jobs:
           - truffleruby-head
     continue-on-error: ${{ endsWith(matrix.ruby, 'head') }}
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v6
     - uses: ruby/setup-ruby@v1
       with:
         ruby-version: ${{ matrix.ruby }}