Bump actions/checkout from 5 to 6 in /.github/workflows

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](https://github.com/actions/checkout/compare/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] <support@github.com>

.github/workflows/__with-checkout-path.yml

@@ -77,7 +77,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     steps:
       - name: Check out repository
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
       - name: Prepare test
         id: prepare-test
         uses: ./.github/actions/prepare-test
@@ -107,7 +107,7 @@ jobs:
           rm -rf ./* .github .git
   # Check out the actions repo again, but at a different location.
   # choose an arbitrary SHA so that we can later test that the commit_oid is not from main
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           ref: 474bbf07f9247ffe1856c6a0f94aeeb10e7afee6
           path: x/y/z/some-path