Bump actions/checkout from 5 to 6 (#308)

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/build-and-publish-antora.yml

@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Setup Node.js
         uses: actions/setup-node@v6

.github/workflows/codeql.yml

@@ -62,7 +62,7 @@ jobs:
         # your codebase is analyzed, see https://docs.github.com/en/code-security/code-scanning/creating-an-advanced-setup-for-code-scanning/codeql-code-scanning-for-compiled-languages
     steps:
     - name: Checkout repository
-      uses: actions/checkout@v5
+      uses: actions/checkout@v6
     - name: Set up JDK
       uses: actions/setup-java@v5
       with:

.github/workflows/gradle-build.yml

@@ -31,7 +31,7 @@ jobs:
       build-changes: ${{ steps.filter.outputs.build }}
       source-changes: ${{ steps.filter.outputs.java }}
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           fetch-depth: 0
       - uses: dorny/paths-filter@v3
@@ -54,7 +54,7 @@ jobs:
     outputs:
       build-artifacts: ${{ steps.upload-build-artifacts.outputs.artifact-id }}
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           fetch-depth: 0      
       - name: Set up JDK
@@ -88,7 +88,7 @@ jobs:
     if: ${{ needs.check-changes.outputs.build-changes == 'true' }}
     steps:
       - name: Checkout sources
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
       - name: Setup Java
         uses: actions/setup-java@v5
         with:
@@ -107,7 +107,7 @@ jobs:
     if: ${{ needs.check-changes.outputs.source-changes == 'true' }}
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           fetch-depth: 0      
       - name: Set up JDK

.github/workflows/gradle-wrapper-updater.yml

@@ -9,7 +9,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
       - name: Set up JDK
         uses: actions/setup-java@v5