feat: ✨ add support for dynu.com as DynDNS2 provider

dynb.sh

@@ -365,6 +365,11 @@ function prepare_request_parameters
       curl_parameters+=("--get") # inwx will ignore the ipv6 parameter if you don't put it into the url
       dyndns_update_url="https://dyndns.inwx.com/nic/update"
     ;;
+    [Dd][Yy][Nn][Uu]*)
+      curl_parameters+=("--user" "$DYNB_USERNAME:$DYNB_PASSWORD")
+      curl_parameters+=("--get")
+      dyndns_update_url="https://api.dynu.com/nic/update"
+    ;;
     [Dd][Ee][Ss][Ee][Cc]* | [Dd][Ee][Dd][Yy][Nn]* )
     # deSEC.de / dedyn.io
       curl_parameters+=("--header" "Authorization: Token $DYNB_TOKEN")
@@ -515,7 +520,7 @@ function analyse_response
       errorMessage "$_response: There is an internal error in the dyndns update system. Retry update no sooner than 30 minutes."
       return 1
       ;;
-    911 | 5*)
+    servererror | 911 | 5*)
       errorMessage "$_response: A fatal error on provider side such as a database outage. Retry update no sooner than 30 minutes."
       return 1
       ;;
@@ -589,7 +594,7 @@ function checkStatus
       echo "If it still fails file an issue at github or try another client :)"
       return 1
       ;;
-    911 | 5* | *'Too Many Requests'*)
+    servererror | 911 | 5* | *'Too Many Requests'*)
       delta=$(($(date +%s) - _eventTime))
       if [[ $delta -lt 1800 ]]
       then