Remove obsolete Group tag

References: https://fedoraproject.org/wiki/Changes/Remove_Group_Tag

Box2D.spec

@@ -3,7 +3,6 @@ Version:  2.3.1
 Release:  9%{?dist}
 Summary: A 2D Physics Engine for Games
 
-Group: Development/Libraries
 License: zlib
 URL: http://box2d.org/
 # "Google Code no longer allows for downloads, therefore you will have to use SVN to get v2.3.1"
@@ -19,7 +18,6 @@ BuildRequires: cmake libXi-devel glew-devel glfw-devel
 
 %package devel
 Summary: Development files for %{name}
-Group: Development/Libraries
 Requires: %{name} = %{version}-%{release}
 
 %description