TUN-7590: Remove usages of ioutil

hello/hello.go

@@ -6,7 +6,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"html/template"
-	"io/ioutil"
+	"io"
 	"net"
 	"net/http"
 	"os"
@@ -234,7 +234,7 @@ func rootHandler(serverName string) http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
 		var buffer bytes.Buffer
 		var body string
-		rawBody, err := ioutil.ReadAll(r.Body)
+		rawBody, err := io.ReadAll(r.Body)
 		if err == nil {
 			body = string(rawBody)
 		} else {