replace io/ioutil to os (#7281)

docs/source/GoUsage.md

@@ -52,10 +52,10 @@ a `[]byte`, which you pass to the `GetRootAsMonster` function:
        example "MyGame/Example"
        flatbuffers "github.com/google/flatbuffers/go"
 
-       io/ioutil
+       "os"
     )
 
-    buf, err := ioutil.ReadFile("monster.dat")
+    buf, err := os.ReadFile("monster.dat")
     // handle err
     monster := example.GetRootAsMonster(buf, 0)
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

tests/go_test.go

@@ -24,7 +24,6 @@ import (
 	"bytes"
 	"flag"
 	"fmt"
-	"io/ioutil"
 	"os"
 	"reflect"
 	"sort"
@@ -101,7 +100,7 @@ func TestAll(t *testing.T) {
 
 	// Verify that the buffer generated by C++ code is readable by the
 	// generated Go code:
-	monsterDataCpp, err := ioutil.ReadFile(cppData)
+	monsterDataCpp, err := os.ReadFile(cppData)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -141,7 +140,7 @@ func TestAll(t *testing.T) {
 	// is given, check that Go code can read it, and that Go code
 	// generates an identical buffer when used to create the example data:
 	if javaData != "" {
-		monsterDataJava, err := ioutil.ReadFile(javaData)
+		monsterDataJava, err := os.ReadFile(javaData)
 		if err != nil {
 			t.Fatal(err)
 		}
@@ -155,7 +154,7 @@ func TestAll(t *testing.T) {
 	}
 
 	// Write the generated buffer out to a file:
-	err = ioutil.WriteFile(outData, generated[off:], os.FileMode(0644))
+	err = os.WriteFile(outData, generated[off:], os.FileMode(0644))
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -1685,7 +1684,7 @@ func CheckSizePrefixedBuffer(fail func(string, ...interface{})) {
 	CheckObjectAPI(generated, off, true, fail)
 
 	// Write generated bfufer out to a file
-	if err := ioutil.WriteFile(outData+".sp", generated[off:], os.FileMode(0644)); err != nil {
+	if err := os.WriteFile(outData+".sp", generated[off:], os.FileMode(0644)); err != nil {
 		fail("failed to write file: %s", err)
 	}
 }