Add libglib2.0-dev to debian/control

GLib is needed for the changes in RadiantApp to intercept and discard unwanted
GTK warning messages to console.

debian/changelog

@@ -1,4 +1,4 @@
-darkradiant (2.11.0~focal1) focal; urgency=medium
+darkradiant (2.11.0~focal2) focal; urgency=medium
 
   * New favourites system for assets like entities, textures and sound shaders.
   * Improved text search in resource browsers.

debian/control

@@ -2,7 +2,7 @@ Source: darkradiant
 Section: editors
 Priority: optional
 Maintainer: Matthew Mott <orbweaver3d@gmail.com>
-Build-Depends: debhelper (>= 10), cmake (>= 3.12), pkg-config, libxml2-dev, libglew-dev, python-dev, libvorbis-dev, libopenal-dev, libalut-dev, libjpeg-dev, libftgl-dev, libwxbase3.0-dev, libwxgtk3.0-gtk3-dev, libsigc++-2.0-dev
+Build-Depends: debhelper (>= 10), cmake (>= 3.12), pkg-config, libxml2-dev, libglew-dev, python-dev, libvorbis-dev, libopenal-dev, libalut-dev, libjpeg-dev, libftgl-dev, libwxbase3.0-dev, libwxgtk3.0-gtk3-dev, libsigc++-2.0-dev, libglib2.0-dev
 Standards-Version: 4.2.1
 
 Package: darkradiant