deps: bump google.golang.org/grpc from 1.22.0 to 1.23.0 (#3942)

Bumps [google.golang.org/grpc](https://github.com/grpc/grpc-go) from 1.22.0 to 1.23.0.
- [Release notes](https://github.com/grpc/grpc-go/releases)
- [Commits](https://github.com/grpc/grpc-go/compare/v1.22.0...v1.23.0)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

go.mod

@@ -42,5 +42,5 @@ require (
 	github.com/tendermint/tm-db v0.1.1
 	golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2
 	golang.org/x/net v0.0.0-20190628185345-da137c7871d7
-	google.golang.org/grpc v1.22.0
+	google.golang.org/grpc v1.23.0
 )

go.sum

@@ -160,6 +160,8 @@ google.golang.org/genproto v0.0.0-20181029155118-b69ba1387ce2 h1:67iHsV9djwGdZpd
 google.golang.org/genproto v0.0.0-20181029155118-b69ba1387ce2/go.mod h1:JiN7NxoALGmiZfu7CAH4rXhgtRTLTxftemlI0sWmxmc=
 google.golang.org/grpc v1.22.0 h1:J0UbZOIrCAl+fpTOf8YLs4dJo8L/owV4LYVtAXQoPkw=
 google.golang.org/grpc v1.22.0/go.mod h1:Y5yQAOtifL1yxbo5wqy6BxZv8vAUGQwXBOALyacEbxg=
+google.golang.org/grpc v1.23.0 h1:AzbTB6ux+okLTzP8Ru1Xs41C303zdcfEht7MQnYJt5A=
+google.golang.org/grpc v1.23.0/go.mod h1:Y5yQAOtifL1yxbo5wqy6BxZv8vAUGQwXBOALyacEbxg=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/fsnotify.v1 v1.4.7 h1:xOHLXZwVvI9hhs+cLKq5+I5onOuwQLhQwiu63xxlHs4=