deps: update dependency io.grpc:grpc-bom to v1.24.0 (#3)

Author: Renovate Bot

pom.xml

@@ -68,7 +68,7 @@
  <google.api-common.version>1.8.1</google.api-common.version>
  <google.common-protos.version>1.17.0</google.common-protos.version>
  <gax.version>1.49.0</gax.version>
- <grpc.version>1.23.0</grpc.version>
+ <grpc.version>1.24.0</grpc.version>
  <protobuf.version>3.10.0</protobuf.version>
  <junit.version>4.12</junit.version>
  <guava.version>28.1-android</guava.version>