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/buildsite.yml

@@ -9,7 +9,7 @@ jobs:
 
     steps:
     - name: Checkout
-      uses: actions/checkout@v4
+      uses: actions/checkout@v6
 
     - name: Install cpanm
       run: |

.github/workflows/perltest.yml

@@ -16,7 +16,7 @@ jobs:
         perl: [ 'latest' ]
     name: Perl ${{ matrix.perl }} on ${{ matrix.os }}
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - name: Set up perl
         uses: shogo82148/actions-setup-perl@v1
         with:
@@ -43,7 +43,7 @@ jobs:
     container: davorg/perl-coveralls:latest
     name: Test coverage
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - run: cpanm --notest File::ShareDir::Install
       - run: cpanm --notest --installdeps .
       - name: Install modules