chore: use mcr alpine image in blobfuse-proxy

Author: andyzhangx

deploy/blobfuse-proxy/blobfuse-proxy.yaml

@@ -55,7 +55,7 @@ spec:
             sleep 3s
             # tail blobfuse proxy logs
             journalctl -u blobfuse-proxy -f
-        image: alpine
+        image: mcr.microsoft.com/oss/nginx/nginx:1.17.3-alpine
         imagePullPolicy: IfNotPresent
         name: sysctl-install-blobfuse-proxy
         resources: