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] <[email protected]>

Author: dependabot[bot]

.github/workflows/main.yml

@@ -20,7 +20,7 @@ jobs:
         perl: [ '5.36.0', '5.34.1', '5.32.1', '5.30.3', '5.28.3', '5.26.3', '5.24.4', '5.22.4', '5.20.3', '5.18.4', '5.16.3', '5.14.4', '5.12.5' ]
     name: Perl ${{ matrix.perl }} on ${{ matrix.os }}
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
         with:
           fetch-depth: 0
       - name: Set up perl