Remove obsolete Group tag

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

libgta.spec

@@ -2,7 +2,6 @@ Name:      libgta
 Version:   1.0.9
 Release:   1%{?dist}
 Summary:   Library that implements the Generic Tagged Arrays file format
-Group:     System Environment/Libraries
 License:   LGPLv2+
 URL:       https://marlam.de/gta/
 Source0:   https://marlam.de/gta/releases/%{name}-%{version}.tar.xz
@@ -19,7 +18,6 @@ file format. It provides interfaces for C and C++.
 
 %package devel
 Summary:  Development Libraries for %{name}
-Group:    Development/Libraries
 Requires: %{name}%{?_isa} = %{version}-%{release}
 Requires: pkgconfig
 
@@ -30,7 +28,6 @@ developing applications that use %{name}.
 
 %package doc
 Summary:  API documentation for %{name}
-Group:    Documentation
 Requires: %{name} = %{version}-%{release}
 BuildArch: noarch