Caused by: java.lang.ClassNotFoundException: io.grpc.internal.AbstractManagedChannelImplBuilder

Recent change efd21fb made some dependencies as test scope and causes the ClassNotFoundException. When publishing the artifacts, we use flatten-maven-plugin, which currently excludes the test-scope dependencies from other dependencies (mojohaus/flatten-maven-plugin#185).

We changed the scope (efd21fb) because the dependencies check had failed with the following message:

Warning:  Non-test scoped test only dependencies found:
Warning:     com.google.http-client:google-http-client:jar:1.42.0:compile
Warning:     io.grpc:grpc-stub:jar:1.47.0:compile
Warning:     io.grpc:grpc-core:jar:1.47.0:compile

CC: @alicejli , @BenWhitehead