Remove obsolete Group tag

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

atkmm.spec

@@ -9,7 +9,6 @@ Version:        2.24.3
 Release:        1%{?dist}
 Summary:        C++ interface for the ATK library
 
-Group:          System Environment/Libraries
 License:        LGPLv2+
 URL:            http://www.gtkmm.org/
 Source0:        http://ftp.gnome.org/pub/GNOME/sources/atkmm/%{release_version}/atkmm-%{version}.tar.xz
@@ -29,7 +28,6 @@ quickly create complex user interfaces.
 
 %package devel
 Summary:        Development files for %{name}
-Group:          Development/Libraries
 Requires:       %{name} = %{version}-%{release}
 
 %description devel
@@ -39,7 +37,6 @@ developing applications that use %{name}.
 
 %package        doc
 Summary:        Developer's documentation for the atkmm library
-Group:          Documentation
 BuildArch:      noarch
 Requires:       %{name} = %{version}-%{release}
 Requires:       glibmm24-doc