Handle ioutil deprecations (#53526)

* replace ioutil.ReadFile -> os.ReadFile

* replace ioutil.ReadAll -> io.ReadAll

* replace ioutil.TempFile -> os.CreateTemp

* replace ioutil.NopCloser -> io.NopCloser

* replace ioutil.WriteFile -> os.WriteFile

* replace ioutil.TempDir -> os.MkdirTemp

* replace ioutil.Discard -> io.Discard

pkg/api/pluginproxy/pluginproxy.go

@@ -3,7 +3,7 @@ package pluginproxy
 import (
 	"bytes"
 	"encoding/json"
-	"io/ioutil"
+	"io"
 	"net/http"
 	"net/http/httputil"
 	"net/url"
@@ -107,9 +107,9 @@ func logAppPluginProxyRequest(appID string, cfg *setting.Cfg, c *models.ReqConte
 
 	var body string
 	if c.Req.Body != nil {
-		buffer, err := ioutil.ReadAll(c.Req.Body)
+		buffer, err := io.ReadAll(c.Req.Body)
 		if err == nil {
-			c.Req.Body = ioutil.NopCloser(bytes.NewBuffer(buffer))
+			c.Req.Body = io.NopCloser(bytes.NewBuffer(buffer))
 			body = string(buffer)
 		}
 	}