Require gnome-themes-extra for gtk3 css files

gnome-tweaks needs the /usr/share/themes/{Adwaita,Adwaita-dark,HighContrast}/gtk-3.0/gtk.css
files that gnome-themes-extra installs to detect which themes are
available.

fixup! Require gnome-themes-extra

gnome-tweaks.spec

@@ -3,7 +3,7 @@
 
 Name:           gnome-tweaks
 Version:        40~beta
-Release:        3%{?dist}
+Release:        4%{?dist}
 Summary:        Customize advanced GNOME 3 options
 
 # Software is GPLv3, Appdata file is CC0-1.0
@@ -20,6 +20,7 @@ Requires:       gnome-desktop3
 Requires:       gnome-settings-daemon
 Requires:       gnome-shell
 Requires:       gnome-shell-extension-user-theme
+Requires:       gnome-themes-extra
 Requires:       gobject-introspection
 Requires:       gsettings-desktop-schemas
 Requires:       gtk3
@@ -84,6 +85,9 @@ appstream-util validate-relax --nonet $RPM_BUILD_ROOT/%{_datadir}/metainfo/*.app
 
 
 %changelog
+* Tue Feb 23 2021 Kalev Lember <klember@redhat.com> - 40~beta-4
+- Require gnome-themes-extra for gtk3 css files
+
 * Thu Feb 18 2021 Kalev Lember <klember@redhat.com> - 40~beta-3
 - Use same pre-release system as in other GNOME packages