ci: bump actions/checkout from 4 to 6 in the github-actions group (#8)

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


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

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/main.yml

@@ -8,7 +8,7 @@ jobs:
   lint:
     runs-on: [self-hosted, Linux, X64]
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - uses: GeiserX/awesome-lint-extra@v1.1.0
         with:
           require_badges: 'true'
@@ -18,7 +18,7 @@ jobs:
     runs-on: [self-hosted, Linux, X64]
     continue-on-error: true
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - uses: lycheeverse/lychee-action@v2
         with:
           args: --no-progress --insecure --accept 200..=403 --exclude img.shields.io README.md

.github/workflows/sync-maintainers.yml

@@ -13,7 +13,7 @@ jobs:
   sync:
     runs-on: [self-hosted, Linux, X64]
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
 
       - name: Sync maintainers
         env: