Merge pull request #61 from faucetsdn/renovate/grpcio-tools-1.x

Update dependency grpcio-tools to v1.31.0

Author: lantz

requirements.txt

@@ -1,5 +1,5 @@
 grpcio==1.30.0
-grpcio-tools==1.30.0
+grpcio-tools==1.31.0
 requests==2.24.0
 prometheus_client==0.8.0
 protobuf==3.12.2