Bump actions/checkout from 5 to 6 (#736)

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>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

.github/workflows/gradle-publish.yml

@@ -10,7 +10,7 @@ jobs:
     env:
       ORG_GRADLE_PROJECT_larsgreferBuildCachePassword: ${{ secrets.BUILD_CACHE_PASSWORD }}
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - name: Set up JDK 17
         uses: actions/setup-java@v5
         with:

.github/workflows/gradle.yml

@@ -33,7 +33,7 @@ jobs:
             os: windows-latest
             experimental: true
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
       - uses: graalvm/setup-graalvm@v1
         with:
@@ -71,7 +71,7 @@ jobs:
       matrix:
         api-level: [ 21, 26, 30, 34 ]
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
       - name: Set up JDK 17
         uses: actions/setup-java@v5