refactor(fun/clbot): s#io/ioutil#os

Change-Id: I046edc62aa233fa9fa67ef95df86f6c1bca21538
Reviewed-on: https://cl.snix.dev/c/snix/+/30223
Tested-by: besadii
Autosubmit: Florian Klink <flokli@flokli.de>
Reviewed-by: Ryan Lahfa <masterancpp@gmail.com>

fun/clbot/clbot.go

@@ -5,7 +5,6 @@ import (
 	"crypto/tls"
 	"flag"
 	"fmt"
-	"io/ioutil"
 	"net"
 	"os"
 	"os/signal"
@@ -75,7 +74,7 @@ func mustFixedHostKey(f string) ssh.HostKeyCallback {
 }
 
 func mustPrivateKey(p string) ssh.AuthMethod {
-	pkBytes, err := ioutil.ReadFile(p)
+	pkBytes, err := os.ReadFile(p)
 	if err != nil {
 		log.Exitf("reading SSH private key from %q: %v", p, err)
 	}