Bump actions/checkout from 4.1.4 to 4.1.6 in the github-actions group

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


Updates `actions/checkout` from 4.1.4 to 4.1.6
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@0ad4b8f...a5ac7e5)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: github-actions
...

Signed-off-by: dependabot[bot] <[email protected]>

.github/workflows/validation.yml

@@ -13,6 +13,6 @@ jobs:
     name: Validate against TEI_all
     steps:
       - name: Checkout
-        uses: actions/checkout@0ad4b8fadaa221de15dcec353f45205ec38ea70b # v4.1.4
+        uses: actions/checkout@a5ac7e51b41094c92402da3b24376905380afc29 # v4.1.6
       - name: Validate
         uses: dracor-org/tei-validate-action@94b08b8bf0dd1810fe7962aa59435b46c769bbcb # v1.2.0