deps: update dependency io.grpc:grpc-bom to v1.31.0

Author: renovate-bot

pom.xml

@@ -55,7 +55,7 @@
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
     <site.installationModule>${project.artifactId}</site.installationModule>
 
-    <grpc.version>1.30.2</grpc.version>
+    <grpc.version>1.31.0</grpc.version>
     <gax.version>1.57.1</gax.version>
     <guava.version>29.0-android</guava.version>
     <protobuf.version>3.12.2</protobuf.version>