Stop using deprecated protobuf package

CONTRIBUTING.md

@@ -48,8 +48,7 @@ _This step is not necessary unless you are making changes to protobuf definition
 
 Ensure you have the required tools installed, and that `GOPATH` is set.
 ```bash
-go get -u github.com/golang/protobuf/protoc-gen-go
-go install github.com/golang/protobuf/protoc-gen-go
+go install google.golang.org/protobuf/cmd/protoc-gen-go
 export GOBIN=$GOPATH/bin
 export PATH=$PATH:$GOBIN
 export DEST_DIR=$GOPATH/src

cluster/client.go

@@ -9,9 +9,9 @@ import (
 	"sync"
 	"time"
 
-	"github.com/golang/protobuf/proto"
 	"github.com/rqlite/rqlite/command"
 	"github.com/rqlite/rqlite/tcp/pool"
+	"google.golang.org/protobuf/proto"
 )
 
 const (

cluster/service.go

@@ -12,8 +12,8 @@ import (
 	"sync"
 	"time"
 
-	"github.com/golang/protobuf/proto"
 	"github.com/rqlite/rqlite/command"
+	"google.golang.org/protobuf/proto"
 )
 
 // stats captures stats for the Cluster service.

command/marshal.go

@@ -7,7 +7,7 @@ import (
 	"fmt"
 	"io/ioutil"
 
-	"github.com/golang/protobuf/proto"
+	"google.golang.org/protobuf/proto"
 )
 
 const (

command/marshal_test.go

@@ -4,7 +4,7 @@ import (
 	"sync"
 	"testing"
 
-	"github.com/golang/protobuf/proto"
+	"google.golang.org/protobuf/proto"
 )
 
 func Test_NewRequestMarshaler(t *testing.T) {

go.mod

@@ -6,7 +6,6 @@ require (
 	github.com/Bowery/prompt v0.0.0-20190916142128-fa8279994f75
 	github.com/armon/go-metrics v0.3.10 // indirect
 	github.com/fatih/color v1.13.0 // indirect
-	github.com/golang/protobuf v1.5.2
 	github.com/hashicorp/go-cleanhttp v0.5.2 // indirect
 	github.com/hashicorp/go-hclog v1.1.0 // indirect
 	github.com/hashicorp/go-immutable-radix v1.3.1 // indirect
@@ -21,7 +20,7 @@ require (
 	github.com/mkideal/pkg v0.1.3
 	github.com/rqlite/go-sqlite3 v1.22.0
 	github.com/rqlite/raft-boltdb v0.0.0-20211018013422-771de01086ce
-	github.com/rqlite/rqlite-disco-clients v0.0.0-20220119143504-8b316f2862ba
+	github.com/rqlite/rqlite-disco-clients v0.0.0-20220119185651-ab01e15666dd
 	go.uber.org/atomic v1.9.0 // indirect
 	go.uber.org/multierr v1.7.0 // indirect
 	go.uber.org/zap v1.20.0 // indirect

go.sum

@@ -246,8 +246,8 @@ github.com/rqlite/go-sqlite3 v1.22.0 h1:twqvKzylJXG62Qe0rcqdy5ClGhc0YRc2vvA3nEXw
 github.com/rqlite/go-sqlite3 v1.22.0/go.mod h1:ml55MVv28UP7V8zrxILd2EsrI6Wfsz76YSskpg08Ut4=
 github.com/rqlite/raft-boltdb v0.0.0-20211018013422-771de01086ce h1:sVlzmCJiaM0LGK3blAHOD/43QxJZ8bLCDcsqZRatnFE=
 github.com/rqlite/raft-boltdb v0.0.0-20211018013422-771de01086ce/go.mod h1:mc+WNDHyskdViYAoPnaMXEBnSKBmoUgiEZjrlAj6G34=
-github.com/rqlite/rqlite-disco-clients v0.0.0-20220119143504-8b316f2862ba h1:85k9Qkc0B76RVBXWhahVrjb9ShfZU1m0SqEO7RRcqBU=
-github.com/rqlite/rqlite-disco-clients v0.0.0-20220119143504-8b316f2862ba/go.mod h1:pym85nj6JnCI7rM9RxTZ4cubkTQyyg7uLwVydso9B80=
+github.com/rqlite/rqlite-disco-clients v0.0.0-20220119185651-ab01e15666dd h1:Ft0ptZDslycrPSGYrusbWuWcQawp7rSmJ2SchV2dH18=
+github.com/rqlite/rqlite-disco-clients v0.0.0-20220119185651-ab01e15666dd/go.mod h1:pym85nj6JnCI7rM9RxTZ4cubkTQyyg7uLwVydso9B80=
 github.com/ryanuber/columnize v0.0.0-20160712163229-9b3edd62028f/go.mod h1:sm1tb6uqfes/u+d4ooFouqFdy9/2g9QGwK3SQygK0Ts=
 github.com/sean-/seed v0.0.0-20170313163322-e2103e2c3529 h1:nn5Wsu0esKSJiIVhscUtVbo7ada43DJhG55ua/hjS5I=
 github.com/sean-/seed v0.0.0-20170313163322-e2103e2c3529/go.mod h1:DxrIzT+xaE7yg65j358z/aeFdxmN0P9QXhEzd20vsDc=