Bump helm/chart-testing-action from 2.7.0 to 2.8.0 (#2153)

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] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Jina Jain <jjain@splunk.com>

Author: dependabot[bot]

.github/workflows/helm-test.yaml

@@ -20,7 +20,7 @@ jobs:
           version: v3.18.0
 
       - name: Set up chart-testing
-        uses: helm/chart-testing-action@v2.7.0
+        uses: helm/chart-testing-action@v2.8.0
         with:
           version: v3.12.0