Update helm/chart-testing-action action to v2.7.0 (#96)

Co-authored-by: Renovate Bot <[email protected]>

Author: ata-no-one

.github/workflows/ci.yaml

@@ -47,7 +47,7 @@ jobs:
           python-version: 3
 
       - name: Set up chart-testing
-        uses: helm/chart-testing-action@v2.6.1
+        uses: helm/chart-testing-action@v2.7.0
 
       - name: Extract tag
         id: extract_tag