Fix monitor deployment

deploy/monitor-dep.yaml

@@ -14,7 +14,7 @@ spec:
       containers:
       - name: monitor
         image: {{ CI_REGISTRY_IMAGE }}/grpc:latest
-        cmd: "greeter_monitor.py"
+        command: "greeter_monitor.py"
         env:
         - name: GRPC_SVC
           value: grpc-svc