fix grep error when txt value begin with - char

dnsapi/dns_ali.sh

@@ -185,7 +185,7 @@ _clean() {
     return 1
   fi
 
-  record_id="$(echo "$response" | tr '{' "\n" | grep "$_sub_domain" | grep "$txtvalue" | tr "," "\n" | grep RecordId | cut -d '"' -f 4)"
+  record_id="$(echo "$response" | tr '{' "\n" | grep "$_sub_domain" | grep -- "$txtvalue" | tr "," "\n" | grep RecordId | cut -d '"' -f 4)"
   _debug2 record_id "$record_id"
 
   if [ -z "$record_id" ]; then