Bump dieghernan/cff-validator from 2.3 to 3

Bumps [dieghernan/cff-validator](https://github.com/dieghernan/cff-validator) from 2.3 to 3.
- [Release notes](https://github.com/dieghernan/cff-validator/releases)
- [Changelog](https://github.com/dieghernan/cff-validator/blob/main/CHANGELOG.md)
- [Commits](dieghernan/cff-validator@v2.3...v3)

---
updated-dependencies:
- dependency-name: dieghernan/cff-validator
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

.github/workflows/citations.yml

@@ -21,4 +21,4 @@ jobs:
     - name: checkout
       uses: actions/checkout@v4
     - name: Validate CITATION.cff
-      uses: dieghernan/cff-validator@v2.3
+      uses: dieghernan/cff-validator@v3