Update module google.golang.org/grpc to v1.42.0

go.mod

go.sum

vendor/google.golang.org/grpc/.travis.yml

vendor/google.golang.org/grpc/MAINTAINERS.md

vendor/google.golang.org/grpc/Makefile

vendor/google.golang.org/grpc/NOTICE.txt

vendor/google.golang.org/grpc/README.md

vendor/google.golang.org/grpc/attributes/attributes.go

vendor/google.golang.org/grpc/balancer/balancer.go

vendor/google.golang.org/grpc/balancer/base/balancer.go

vendor/google.golang.org/grpc/balancer/grpclb/state/state.go

.../google.golang.org/grpc/balancer/roundrobin/roundrobin.go

vendor/google.golang.org/grpc/balancer_conn_wrappers.go

vendor/google.golang.org/grpc/clientconn.go

vendor/google.golang.org/grpc/connectivity/connectivity.go

vendor/google.golang.org/grpc/credentials/credentials.go

vendor/google.golang.org/grpc/credentials/go12.go

vendor/google.golang.org/grpc/credentials/tls.go

vendor/google.golang.org/grpc/dialoptions.go

vendor/google.golang.org/grpc/go.mod