gha: bump actions/checkout from 5 to 6 in the github-actions group

Bumps the github-actions group with 1 update: [actions/checkout](https://github.com/actions/checkout).


Updates `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
  dependency-group: github-actions
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

.github/workflows/check.yml

@@ -52,7 +52,7 @@ jobs:
       matrix:
         format: [ html, latex, epub ]
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           fetch-depth: 5
 
@@ -135,7 +135,7 @@ jobs:
     name: Lint translations
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           fetch-depth: 5
 
@@ -195,7 +195,7 @@ jobs:
     name: Check for zero-width space characters
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           ref: ${{ inputs.version }}
 

.github/workflows/sync.yml

@@ -30,14 +30,14 @@ jobs:
       # 1- Set up environment
 
       - name: Check out this repository
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Set language dir variable
         run:
           echo "PYDOC_LANG_DIR=${{ env.PYDOC_VERSION }}" >> $GITHUB_ENV
 
       - name: Checkout this repository ${{ env.PYDOC_VERSION }}
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
         with:
           ref: ${{ env.PYDOC_VERSION }}
           path: ${{ env.PYDOC_LANG_DIR }}