build(deps): bump helm/chart-testing-action from 2.4.0 to 2.6.0 (#554)

Bumps [helm/chart-testing-action](https://github.com/helm/chart-testing-action) from 2.4.0 to 2.6.0.
- [Release notes](https://github.com/helm/chart-testing-action/releases)
- [Commits](helm/chart-testing-action@v2.4.0...v2.6.0)

---
updated-dependencies:
- dependency-name: helm/chart-testing-action
  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>

.github/workflows/ci.yml

@@ -114,7 +114,7 @@ jobs:
           python-version: 3.7
 
       - name: Set up chart-testing
-        uses: helm/chart-testing-action@v2.4.0
+        uses: helm/chart-testing-action@v2.6.0
 
       - name: Add Bitnami Repository
         run: helm repo add bitnami https://charts.bitnami.com/bitnami

.github/workflows/release.yaml

@@ -90,7 +90,7 @@ jobs:
           python-version: 3.7
 
       - name: Set up chart-testing
-        uses: helm/chart-testing-action@v2.4.0
+        uses: helm/chart-testing-action@v2.6.0
 
       - name: Add Bitnami Repository
         run: helm repo add bitnami https://charts.bitnami.com/bitnami