Fix build error for Ruby 3

(cherry picked from commit 0ce0d75737012970ef81b0abad61e8ba80f86885)

rubygem-yard.spec

@@ -1,7 +1,7 @@
 %global gem_name yard
 Name:                rubygem-%{gem_name}
 Version:             0.9.26
-Release:             1
+Release:             2
 Summary:             Documentation tool for consistent and usable documentation in Ruby
 License:             MIT and (BSD or Ruby)
 URL:                 http://yardoc.org
@@ -9,7 +9,7 @@ Source0:             https://rubygems.org/gems/%{gem_name}-%{version}.gem
 Source1:             %{gem_name}-%{version}-spec.txz
 
 BuildRequires:       ruby(release) rubygems-devel ruby rubygem(RedCloth) rubygem(asciidoctor) rubygem(bundler)
-BuildRequires:       rubygem(rspec) rubygem(redcarpet) rubygem(rack)
+BuildRequires:       rubygem(rspec) rubygem(redcarpet) rubygem(rack) rubygem(webrick)
 BuildArch:           noarch
 %description
 YARD is a documentation generation tool for the Ruby programming language.
@@ -75,12 +75,16 @@ popd
 %{gem_instdir}/Rakefile
 %doc %{gem_instdir}/SECURITY.md
 %{gem_instdir}/benchmarks
+%{gem_plugin}
 %{gem_instdir}/tasks
 %doc %{gem_instdir}/docs
 %{gem_instdir}/samus.json
 %{gem_instdir}/%{gem_name}.gemspec
 
 %changelog
+* Sat Jan 22 2022 liyanan <liyanan32@huawei.com> - 0.9.26-2
+- Fix build error for Ruby 3
+
 * Mon Jul 26 2021 houyingchao <houyingchao@huawei.com> - 0.9.26-1
 - Upgrade to 0.9.26