make staticcheck happy

desc_source.go

@@ -5,7 +5,7 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"io/ioutil"
+	"os"
 	"sync"
 
 	"github.com/golang/protobuf/proto" //lint:ignore SA1019 we have to import this because it appears in exported API
@@ -41,7 +41,7 @@ type DescriptorSource interface {
 func DescriptorSourceFromProtoSets(fileNames ...string) (DescriptorSource, error) {
 	files := &descriptorpb.FileDescriptorSet{}
 	for _, fileName := range fileNames {
-		b, err := ioutil.ReadFile(fileName)
+		b, err := os.ReadFile(fileName)
 		if err != nil {
 			return nil, fmt.Errorf("could not load protoset file %q: %v", fileName, err)
 		}

desc_source_test.go

@@ -2,7 +2,7 @@ package grpcurl
 
 import (
 	"bytes"
-	"io/ioutil"
+	"os"
 	"testing"
 
 	"github.com/golang/protobuf/proto" //lint:ignore SA1019 we have to import this because it appears in exported API
@@ -34,7 +34,7 @@ func TestWriteProtoset(t *testing.T) {
 }
 
 func loadProtoset(path string) (*descriptorpb.FileDescriptorSet, error) {
-	b, err := ioutil.ReadFile(path)
+	b, err := os.ReadFile(path)
 	if err != nil {
 		return nil, err
 	}

grpcurl.go

@@ -14,7 +14,6 @@ import (
 	"encoding/base64"
 	"errors"
 	"fmt"
-	"io/ioutil"
 	"net"
 	"os"
 	"regexp"
@@ -545,7 +544,7 @@ func ClientTLSConfig(insecureSkipVerify bool, cacertFile, clientCertFile, client
 	} else if cacertFile != "" {
 		// Create a certificate pool from the certificate authority
 		certPool := x509.NewCertPool()
-		ca, err := ioutil.ReadFile(cacertFile)
+		ca, err := os.ReadFile(cacertFile)
 		if err != nil {
 			return nil, fmt.Errorf("could not read ca certificate: %v", err)
 		}
@@ -582,7 +581,7 @@ func ServerTransportCredentials(cacertFile, serverCertFile, serverKeyFile string
 	if cacertFile != "" {
 		// Create a certificate pool from the certificate authority
 		certPool := x509.NewCertPool()
-		ca, err := ioutil.ReadFile(cacertFile)
+		ca, err := os.ReadFile(cacertFile)
 		if err != nil {
 			return nil, fmt.Errorf("could not read ca certificate: %v", err)
 		}

internal/testing/cmd/bankdemo/main.go

@@ -7,7 +7,6 @@ import (
 	"encoding/json"
 	"flag"
 	"fmt"
-	"io/ioutil"
 	"net"
 	"os"
 	"os/signal"
@@ -130,7 +129,7 @@ type svr struct {
 }
 
 func (s *svr) load() error {
-	accts, err := ioutil.ReadFile(s.datafile)
+	accts, err := os.ReadFile(s.datafile)
 	if err != nil && !os.IsNotExist(err) {
 		return err
 	}
@@ -162,7 +161,7 @@ func (s *svr) flush() {
 
 	if b, err := json.Marshal(accounts); err != nil {
 		grpclog.Errorf("failed to save data to %q", s.datafile)
-	} else if err := ioutil.WriteFile(s.datafile, b, 0666); err != nil {
+	} else if err := os.WriteFile(s.datafile, b, 0666); err != nil {
 		grpclog.Errorf("failed to save data to %q", s.datafile)
 	}
 }