Move to debhelper-compat 12

Temporarily disable dh_dwz to make diffoscope more useful.

debian/compat

-11

debian/control

@@ -7,7 +7,7 @@ Section: gnome
 Priority: optional
 Maintainer: Debian GNOME Maintainers <pkg-gnome-maintainers@lists.alioth.debian.org>
 Uploaders: Iain Lane <laney@debian.org>, Jeremy Bicha <jbicha@debian.org>, Michael Biebl <biebl@debian.org>
-Build-Depends: debhelper (>= 11.1.3),
+Build-Depends: debhelper-compat (= 12),
                libaccountsservice-dev (>= 0.6.39),
                desktop-file-utils,
                gnome-pkg-tools (>= 0.10),

debian/control.in

@@ -3,7 +3,7 @@ Section: gnome
 Priority: optional
 Maintainer: Debian GNOME Maintainers <pkg-gnome-maintainers@lists.alioth.debian.org>
 Uploaders: @GNOME_TEAM@
-Build-Depends: debhelper (>= 11.1.3),
+Build-Depends: debhelper-compat (= 12),
                libaccountsservice-dev (>= 0.6.39),
                desktop-file-utils,
                gnome-pkg-tools (>= 0.10),

debian/rules

@@ -15,3 +15,5 @@ override_dh_auto_configure:
 
 override_dh_missing:
 	dh_missing --fail-missing
+
+override_dh_dwz: