chore: remove refs to deprecated io/ioutil (#70300)

devenv/docker/ha-test-unified-alerting/webhook-listener.go

@@ -4,7 +4,7 @@ import (
 	"encoding/json"
 	"flag"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"log"
 	"net/http"
 	"os"
@@ -129,7 +129,7 @@ func main() {
 
 	http.HandleFunc("/listen", func(w http.ResponseWriter, r *http.Request) {
 		log.Printf("got submission from: %s\n", r.RemoteAddr)
-		b, err := ioutil.ReadAll(r.Body)
+		b, err := io.ReadAll(r.Body)
 		if err != nil {
 			log.Println(err)
 			w.WriteHeader(http.StatusBadRequest)

pkg/services/ngalert/sender/notifier_ext.go

@@ -12,7 +12,6 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"net/http"
 	"sync"
 	"time"
@@ -184,7 +183,7 @@ func (n *Manager) sendOne(ctx context.Context, c *http.Client, url string, b []b
 		return err
 	}
 	defer func() {
-		io.Copy(ioutil.Discard, resp.Body)
+		io.Copy(io.Discard, resp.Body)
 		resp.Body.Close()
 	}()