Re-add rexml dependency

While it is being provided by Ruby, it does not get installed
automatically (since it is a subpackage since Ruby 3.0.0).

Signed-off-by: Igor Raits <ignatenkobrain@fedoraproject.org>

rubygem-kramdown.spec

@@ -3,7 +3,7 @@
 
 Name: rubygem-%{gem_name}
 Version: 2.2.1
-Release: 6%{?dist}
+Release: 7%{?dist}
 Summary: Fast, pure-Ruby Markdown-superset converter
 
 License:	MIT
@@ -53,10 +53,6 @@ gem unpack %{SOURCE0}
 %setup -q -D -T -n  %{gem_name}-%{version}
 %patch1 -p1
 gem spec %{SOURCE0} -l --ruby > %{gem_name}.gemspec
-# 2.2.1 explicily adds rexml runtime dependency, which is actually provided by system ruby.
-# So writing it to kramdown gemspec is not strictly needed, removing for now
-# (bug 1838185)
-sed -i %{gem_name}.gemspec -e '\@rexml@d'
 
 %build
 gem build %{gem_name}.gemspec
@@ -115,6 +111,9 @@ popd
 %doc	%{gem_docdir}
 
 %changelog
+* Wed Jan 13 2021 Igor Raits <ignatenkobrain@fedoraproject.org> - 2.2.1-7
+- Re-add rexml dependency
+
 * Fri Oct  2 2020 Mamoru TASAKA <mtasaka@fedoraproject.org> - 2.2.1-6
 - Test suite now failing, rescuing now