F-36: rebuild against ruby31

modernize spec file, especially move %gem_install to %build
  to fix FTBFS with package_notes

rubygem-http_parser.rb.spec

@@ -3,7 +3,7 @@
 
 Name:		rubygem-%{gem_name}
 Version:	0.6.0
-Release:	23%{?dist}
+Release:	24%{?dist}
 Summary:	Simple callback-based HTTP request/response parser
 License:	MIT
 URL:		https://github.com/tmm1/http_parser.rb
@@ -34,20 +34,11 @@ BuildArch:	noarch
 Documentation for %{name}.
 
 %prep
-gem unpack %{SOURCE0}
-
-%setup -q -D -T -n  %{gem_name}-%{version}
-
-gem spec %{SOURCE0} -l --ruby > %{gem_name}.gemspec
-%patch0 -p1
-%patch1 -p1
-
-gem build %{gem_name}.gemspec
-
-export CONFIGURE_ARGS="--with-cflags='%{optflags}'"
-%gem_install
+%autosetup -n %{gem_name}-%{version} -p1
 
 %build
+gem build ../%{gem_name}-%{version}.gemspec
+%gem_install
 
 %install
 mkdir -p %{buildroot}%{gem_dir}
@@ -95,6 +86,11 @@ popd
 %{gem_instdir}/tasks
 
 %changelog
+* Thu Jan 27 2022 Mamoru TASAKA <mtasaka@fedoraproject.org> - 0.6.0-24
+- F-36: rebuild against ruby31
+- modernize spec file, especially move %%gem_install to %%build
+  to fix FTBFS with package_notes
+
 * Fri Jan 21 2022 Fedora Release Engineering <releng@fedoraproject.org> - 0.6.0-23
 - Rebuilt for https://fedoraproject.org/wiki/Fedora_36_Mass_Rebuild