Modernize package and make the watch file work.

debian/compat

@@ -1 +0,0 @@
-11

debian/control

@@ -4,11 +4,11 @@ Priority: optional
 Maintainer: Lubuntu Developers <lubuntu-devel@lists.ubuntu.com>
 Uploaders: Simon Quigley <tsimonq2@ubuntu.com>
 Build-Depends: cmake,
-               debhelper (>= 11),
+               debhelper-compat (= 12),
                libjson-glib-dev,
                libmagic-dev,
                lxqt-build-tools
-Standards-Version: 4.1.5
+Standards-Version: 4.5.0
 Homepage: https://github.com/lxqt/lxqt-archiver
 Vcs-Browser: https://phab.lubuntu.me/source/lxqt-archiver/
 Vcs-Git: https://phab.lubuntu.me/source/lxqt-archiver.git

debian/copyright

@@ -8,7 +8,7 @@ Copyright: 2001-2012 The Free Software Foundation, Inc.
 License: GPL-2+
 
 Files: debian/*
-Copyright: 2018 Lubuntu Developers <lubuntu-devel@lists.ubuntu.com>
+Copyright: 2018-2020 Lubuntu Developers <lubuntu-devel@lists.ubuntu.com>
 License: GPL-2+
 
 License: GPL-2+

debian/watch

@@ -1,3 +1,2 @@
 version=4
-opts="pgpsigurlmangle=s/$/.asc/" \
-https://github.com/lxqt/lxqt-archiver/releases .*/lxqt-archiver-([\d\.]+).tar.xz
+https://github.com/lxqt/lxqt-archiver/releases .*/([\d\.]+).tar.gz