refactor: move from io/ioutil to io and os package

The io/ioutil package has been deprecated as of Go 1.16, see
https://golang.org/doc/go1.16#ioutil. This commit replaces the existing
io/ioutil functions with their new definitions in io and os packages.

Signed-off-by: Eng Zer Jun <engzerjun@gmail.com>

weed/operation/chunked_file.go

@@ -4,9 +4,7 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
-	"github.com/chrislusf/seaweedfs/weed/pb"
 	"io"
-	"io/ioutil"
 	"net/http"
 	"sort"
 	"sync"
@@ -14,6 +12,7 @@ import (
 	"google.golang.org/grpc"
 
 	"github.com/chrislusf/seaweedfs/weed/glog"
+	"github.com/chrislusf/seaweedfs/weed/pb"
 	"github.com/chrislusf/seaweedfs/weed/util"
 )
 
@@ -108,7 +107,7 @@ func readChunkNeedle(fileUrl string, w io.Writer, offset int64, jwt string) (wri
 		return written, err
 	}
 	defer func() {
-		io.Copy(ioutil.Discard, resp.Body)
+		io.Copy(io.Discard, resp.Body)
 		resp.Body.Close()
 	}()
 

weed/operation/upload_content.go

@@ -5,7 +5,6 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"mime"
 	"mime/multipart"
 	"net/http"
@@ -91,7 +90,7 @@ func doUpload(reader io.Reader, option *UploadOption) (uploadResult *UploadResul
 	if ok {
 		data = bytesReader.Bytes
 	} else {
-		data, err = ioutil.ReadAll(reader)
+		data, err = io.ReadAll(reader)
 		if err != nil {
 			err = fmt.Errorf("read input: %v", err)
 			return
@@ -278,7 +277,7 @@ func upload_content(fillBufferFunction func(w io.Writer) error, originalDataSize
 		return &ret, nil
 	}
 
-	resp_body, ra_err := ioutil.ReadAll(resp.Body)
+	resp_body, ra_err := io.ReadAll(resp.Body)
 	if ra_err != nil {
 		return nil, fmt.Errorf("read response body %v: %v", option.UploadUrl, ra_err)
 	}