Merge pull request #469 from cybozu-go/set-output

Stop using set-output

.github/workflows/helm.yaml

@@ -28,7 +28,7 @@ jobs:
         run: |
           changed=$(ct list-changed --config ct.yaml)
           if [[ -n "$changed" ]]; then
-            echo "::set-output name=changed::true"
+            echo "changed=true" >> $GITHUB_OUTPUT
           fi
       - name: Run chart-testing (lint)
         run: ct lint --config ct.yaml