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] <support@github.com>

Author: dependabot[bot]

.github/workflows/macos.yml

@@ -28,7 +28,7 @@ jobs:
         git config --global core.autocrlf false
         git config --global core.eol lf
         git config --global advice.detachedHead 0
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
     - name: Set up Ruby
       uses: ruby/setup-ruby@v1
       with:

.github/workflows/release.yml

@@ -8,7 +8,7 @@ jobs:
     runs-on: ubuntu-latest
     timeout-minutes: 10
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - name: Extract release note
         run: |
           ruby \
@@ -40,7 +40,7 @@ jobs:
           - ruby
           - jruby
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: ruby/setup-ruby@v1
         with:
           ruby-version: ${{ matrix.ruby }}

.github/workflows/sync-ruby.yml

@@ -8,7 +8,7 @@ jobs:
     runs-on: ubuntu-latest
     if: ${{ github.repository_owner == 'ruby' }}
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
       - name: Create GitHub App token
         id: app-token

.github/workflows/ubuntu.yml

@@ -28,7 +28,7 @@ jobs:
         git config --global core.autocrlf false
         git config --global core.eol lf
         git config --global advice.detachedHead 0
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
     - uses: actions/setup-java@v5
       with:
         distribution: zulu

.github/workflows/windows.yml

@@ -29,7 +29,7 @@ jobs:
         git config --global core.autocrlf false
         git config --global core.eol lf
         git config --global advice.detachedHead 0
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
     - uses: actions/setup-java@v5
       with:
         distribution: zulu