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] <[email protected]>

Author: dependabot[bot]

.github/workflows/build_offline_docs.yml

@@ -24,7 +24,7 @@ jobs:
     permissions:
       contents: write
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           ref: ${{ matrix.branch }}
 

.github/workflows/check_urls.yml

@@ -11,7 +11,7 @@ jobs:
     runs-on: ubuntu-24.04
     steps:
 
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
       - name: Restore lychee cache
         uses: actions/cache@v5

.github/workflows/cherrypick.yml

@@ -35,7 +35,7 @@ jobs:
 
     steps:
     - name: Checkout
-      uses: actions/checkout@v5
+      uses: actions/checkout@v6
       with:
         ref: ${{ env.TARGET_BRANCH }}
 

.github/workflows/ci.yml

@@ -14,7 +14,7 @@ jobs:
     timeout-minutes: 120
     steps:
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Style checks via pre-commit
         uses: pre-commit/[email protected]

.github/workflows/sync_class_ref.yml

@@ -30,10 +30,10 @@ jobs:
 
     steps:
       - name: Checkout the documentation repository
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Checkout the engine repository
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
         with:
           repository: 'godotengine/godot'
           # Use the appropriate branch for the documentation version.