Bump actions/checkout from 5 to 6 (#8276)

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](https://github.com/actions/checkout/compare/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>

.github/workflows/docker-publish.yml

@@ -46,7 +46,7 @@ jobs:
       uses: docker/setup-buildx-action@v3
 
     - name: Checkout
-      uses: actions/checkout@v5
+      uses: actions/checkout@v6
 
     - name: Get FreshRSS version
       run: |

.github/workflows/dockerhub-description.yml

@@ -13,7 +13,7 @@ jobs:
     if: github.repository_owner == 'FreshRSS'
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
 
     - name: Update repo description
       uses: peter-evans/dockerhub-description@1b9a80c056b620d92cedb9d9b5a223409c68ddfa

.github/workflows/jekyll-gh-pages.yml

@@ -27,7 +27,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
       - name: Setup Pages
         uses: actions/configure-pages@v5
       - name: Build with Jekyll

.github/workflows/tests.yml

@@ -14,7 +14,7 @@ jobs:
 
     steps:
     - name: Git checkout source code
-      uses: actions/checkout@v5
+      uses: actions/checkout@v6
 
     # Composer tests