build(deps): Bump github.com/cosmos/iavl from 0.15.3 to 0.16.0

Bumps [github.com/cosmos/iavl](https://github.com/cosmos/iavl) from 0.15.3 to 0.16.0.
- [Release notes](https://github.com/cosmos/iavl/releases)
- [Changelog](https://github.com/cosmos/iavl/blob/master/CHANGELOG.md)
- [Commits](cosmos/iavl@v0.15.3...v0.16.0)

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

go.mod

@@ -8,16 +8,16 @@ require (
 	github.com/Workiva/go-datastructures v1.0.52
 	github.com/btcsuite/btcd v0.21.0-beta
 	github.com/btcsuite/btcutil v1.0.2
-	github.com/confio/ics23/go v0.6.3
-	github.com/cosmos/iavl v0.15.3
+	github.com/confio/ics23/go v0.6.6
+	github.com/cosmos/iavl v0.16.0
 	github.com/fortytw2/leaktest v1.3.0
 	github.com/go-kit/kit v0.10.0
 	github.com/go-logfmt/logfmt v0.5.0
 	github.com/gogo/protobuf v1.3.2
-	github.com/golang/protobuf v1.4.3
+	github.com/golang/protobuf v1.5.2
 	github.com/google/orderedcode v0.0.1
 	github.com/gorilla/websocket v1.4.2
-	github.com/grpc-ecosystem/go-grpc-middleware v1.2.2
+	github.com/grpc-ecosystem/go-grpc-middleware v1.3.0
 	github.com/grpc-ecosystem/go-grpc-prometheus v1.2.0
 	github.com/gtank/merlin v0.1.1
 	github.com/hdevalence/ed25519consensus v0.0.0-20201207055737-7fde80a9d5ff
@@ -35,5 +35,5 @@ require (
 	github.com/tendermint/tm-db v0.6.4
 	golang.org/x/crypto v0.0.0-20201117144127-c1f2f97bffc9
 	golang.org/x/net v0.0.0-20201021035429-f5854403a974
-	google.golang.org/grpc v1.36.0
+	google.golang.org/grpc v1.37.0
 )