dependabot(deps): bump helm/chart-testing-action from 2.7.0 to 2.8.0

Bumps [helm/chart-testing-action](https://github.com/helm/chart-testing-action) from 2.7.0 to 2.8.0.
- [Release notes](https://github.com/helm/chart-testing-action/releases)
- [Commits](helm/chart-testing-action@v2.7.0...v2.8.0)

---
updated-dependencies:
- dependency-name: helm/chart-testing-action
  dependency-version: 2.8.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

.github/workflows/ci-chart.yaml

@@ -21,7 +21,7 @@ jobs:
           python-version: '3.12'
           check-latest: true
       - name: Set up chart-testing
-        uses: helm/chart-testing-action@v2.7.0
+        uses: helm/chart-testing-action@v2.8.0
       - name: Run chart-testing (list-changed)
         id: list-changed
         run: |