upgrade helm action to v2.1

Author: therealmitchconnors

.github/workflows/inject-sidecar.yaml

@@ -25,7 +25,7 @@ jobs:
         uses: istio/[email protected]
         with:
           version: ${{ env.ISTIO_VERSION }}
-      - uses: azure/setup-helm@v1
+      - uses: azure/setup-helm@v2.1
         id: install
       - name: Get Istioctl
         run: |