Updated the default push url to the new path
This updates the default push url to https://push.ubports.com:5003/_matrix/push/v1/notify
because the current url was giving the error qml: ERROR: {"errcode":"M_MISSING_PARAM","error":"Config Error: 'url' must have a path of '/_matrix/push/v1/notify'"}
.
Support for this has already been added to the ubports push server: https://github.com/Flohack74/matrix-pushgw/blob/ubuntu-push-module/matrix-pushgw.go#L233