remove deprecated of package io/ioutil (#3395)

context.go

@@ -7,7 +7,6 @@ package gin
 import (
 	"errors"
 	"io"
-	"io/ioutil"
 	"log"
 	"math"
 	"mime/multipart"
@@ -753,7 +752,7 @@ func (c *Context) ShouldBindBodyWith(obj any, bb binding.BindingBody) (err error
 		}
 	}
 	if body == nil {
-		body, err = ioutil.ReadAll(c.Request.Body)
+		body, err = io.ReadAll(c.Request.Body)
 		if err != nil {
 			return err
 		}
@@ -872,7 +871,7 @@ func (c *Context) GetHeader(key string) string {
 
 // GetRawData returns stream data.
 func (c *Context) GetRawData() ([]byte, error) {
-	return ioutil.ReadAll(c.Request.Body)
+	return io.ReadAll(c.Request.Body)
 }
 
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