Remove obsolete Group tag

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

rubygem-hashdiff.spec

@@ -5,7 +5,6 @@ Name: rubygem-%{gem_name}
 Version: 0.3.2
 Release: 4%{?dist}
 Summary: HashDiff is a diff lib to compute the smallest difference between two hashes
-Group: Development/Languages
 License: MIT
 URL: https://github.com/liufengyun/hashdiff
 Source0: https://rubygems.org/gems/%{gem_name}-%{version}.gem
@@ -21,7 +20,6 @@ HashDiff is a diff lib to compute the smallest difference between two hashes.
 
 %package doc
 Summary: Documentation for %{name}
-Group: Documentation
 Requires: %{name} = %{version}-%{release}
 BuildArch: noarch