MT#22619 Switch Debian Source to Sipwise GitHub mirror

Git daemon which provided Sipwise anonymous access to
internal Git repository is deprecated. Also it is
useless to point public GitHub repository to the internal git server.

Change-Id: I61e8380e4559afe0371ffdd993e3444a5330e951

debian/copyright

@@ -1,6 +1,6 @@
 Format: http://www.debian.org/doc/packaging-manuals/copyright-format/1.0/
 Upstream-Name: lua-ngcp-kamailio
-Source: git://git.mgm.sipwise.com/lua-ngcp-kamailio
+Source: https://github.com/sipwise/lua-ngcp-kamailio.git
 
 Files: *
 Copyright: 2013-2014 Sipwise GmbH, Austria