deps: remove pkg errors (#6666)

## Description

remove pkg/errors since we use the provided fmt.Errorf

go.mod

@@ -24,7 +24,6 @@ require (
 	github.com/niemeyer/pretty v0.0.0-20200227124842-a10e7caefd8e // indirect
 	github.com/oasisprotocol/curve25519-voi v0.0.0-20210609091139-0a56a4bca00b
 	github.com/ory/dockertest v3.3.5+incompatible
-	github.com/pkg/errors v0.9.1
 	github.com/prometheus/client_golang v1.11.0
 	github.com/rcrowley/go-metrics v0.0.0-20200313005456-10cdbea86bc0
 	github.com/rs/cors v1.8.0

scripts/keymigrate/migrate.go

@@ -18,7 +18,6 @@ import (
 	"sync"
 
 	"github.com/google/orderedcode"
-	"github.com/pkg/errors"
 	dbm "github.com/tendermint/tm-db"
 )
 
@@ -395,7 +394,7 @@ func Migrate(ctx context.Context, db dbm.DB) error {
 
 	// check the error results
 	if len(errs) != 0 {
-		return errors.Errorf("encountered errors during migration: %v", errStrs)
+		return fmt.Errorf("encountered errors during migration: %v", errStrs)
 	}
 
 	return nil