Change kdenlive repository sending to backports

helpers/make-kdenlive

 #!/bin/sh
 #
+#    Copyright (C) 2021 Luis Guzman <ark@switnet.org>
 #    Copyright (C) 2019 Mason Hock <ruben@trisquel.info>
 #
 #    This program is free software; you can redistribute it and/or modify
@@ -17,12 +18,13 @@
 #    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
 #
 
-VERSION=1
-EXTERNAL='deb-src http://ftp.debian.org/debian testing main'
-REPOKEY=648ACFD622F3D138
+VERSION=2
+EXTERNAL='deb-src http://ppa.launchpad.net/kdenlive/kdenlive-stable/ubuntu $UPSTREAM main'
+REPOKEY=2763B0EE7709FE97
+BACKPORT=true
 
 . ./config
 
-changelog "Backported from debian testing"
+changelog "Backported from official PPA for kdenlive"
 
 compile