Bump actions/checkout from 4 to 6

Bumps [actions/checkout](https://github.com/actions/checkout) from 4 to 6.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v4...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>

Author: dependabot[bot]

.github/workflows/link-checker.yml

@@ -16,7 +16,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
 
       - name: Check links
         uses: lycheeverse/lychee-action@v2

.github/workflows/lint-on-push-pr.yml

@@ -12,7 +12,7 @@ jobs:
     steps:
 
       - name: Checkout repository code
-        uses: actions/checkout@v6.0.2
+        uses: actions/checkout@v6
 
       - name: Set up Node.js
         uses: actions/setup-node@v6.3.0

.github/workflows/sync-changes-to-gitlab.yml

@@ -16,7 +16,7 @@ jobs:
     steps:
 
       - name: Checkout awesome-scripts/awesome-userscripts
-        uses: actions/checkout@v6.0.2
+        uses: actions/checkout@v6
         with:
           fetch-depth: 0