do not use ioutil (#9206)

crypto/armor/armor.go

@@ -3,7 +3,7 @@ package armor
 import (
 	"bytes"
 	"fmt"
-	"io/ioutil"
+	"io"
 
 	"golang.org/x/crypto/openpgp/armor" // nolint: staticcheck
 )
@@ -31,7 +31,7 @@ func DecodeArmor(armorStr string) (blockType string, headers map[string]string,
 	if err != nil {
 		return "", nil, nil, err
 	}
-	data, err = ioutil.ReadAll(block.Body)
+	data, err = io.ReadAll(block.Body)
 	if err != nil {
 		return "", nil, nil, err
 	}