Fix rpc server import

tangostationcontrol/tangostationcontrol/rpc/server.py

@@ -3,7 +3,7 @@ from typing import Dict
 
 import grpc
 import logging
-from prometheus_client import Count, Metric
+from prometheus_client import Counter, Metric
 
 from ._proto import observation_pb2
 from ._proto import observation_pb2_grpc
@@ -40,7 +40,7 @@ class Observation(observation_pb2_grpc.ObservationServicer):
         )
 
     def _add_metric_count(self, name: str, desc: str):
-        self.metrics[name] = Count(
+        self.metrics[name] = Counter(
             name,
             desc,
             ["service"],