fix: add helm redis repo

.github/workflows/deploy-preview.yml

@@ -192,6 +192,7 @@ jobs:
     - name: Create Redis deployment
       if: ${{ steps.helm_redis_deployment.outputs.deployment == 'null' }}
       run: |
+        helm repo add bitnami/redis
         helm --kubeconfig ./kubeconfig.yaml install --set auth.enabled=false ${{ github.event.inputs.preview_name }}-redis bitnami/redis
     - name: Get Helm API deployment
       id: helm_deployment