Drop versioned gtk BR

The versioned dep is old enough to be present in all recent Fedora
releases.

baobab.spec

@@ -1,5 +1,3 @@
-%global gtk3_version 3.24.1
-
 %global tarball_version %%(echo %{version} | tr '~' '.')
 
 Name:           baobab
@@ -11,7 +9,7 @@ License:        GPLv2+ and GFDL
 URL:            https://wiki.gnome.org/Apps/Baobab
 Source0:        https://download.gnome.org/sources/baobab/40/%{name}-%{tarball_version}.tar.xz
 
-BuildRequires:  pkgconfig(gtk+-3.0) >= %{gtk3_version}
+BuildRequires:  pkgconfig(gtk+-3.0)
 BuildRequires:  pkgconfig(libhandy-1)
 BuildRequires:  /usr/bin/appstream-util
 BuildRequires:  desktop-file-utils
@@ -20,8 +18,6 @@ BuildRequires:  itstool
 BuildRequires:  meson
 BuildRequires:  vala
 
-Requires: gtk3%{?_isa} >= %{gtk3_version}
-
 %description
 Baobab is able to scan either specific directories or the whole filesystem, in
 order to give the user a graphical tree representation including each