Update license-plate-reader workers_per_replica to 1 (#845)

Author: deliahu

examples/tensorflow/license-plate-reader/cortex.yaml

@@ -29,5 +29,5 @@
   autoscaling:
     min_replicas: 10
     max_replicas: 10
-    workers_per_replica: 4
+    workers_per_replica: 1
     threads_per_worker: 1