[Manifest] Include the bundler gemspec

This should allow the setup task to succeed when run from the published rubygems-update gem, and not just from source

Author: segiddins

Manifest.txt

@@ -23,6 +23,7 @@ bundler/CODE_OF_CONDUCT.md
 bundler/CONTRIBUTING.md
 bundler/LICENSE.md
 bundler/README.md
+bundler/bundler.gemspec
 bundler/exe/bundle
 bundler/exe/bundle_ruby
 bundler/exe/bundler

Rakefile

@@ -95,7 +95,7 @@ Hoe::Package.instance_method(:install_gem).tap do |existing_install_gem|
   end
 end
 
-Hoe::DEFAULT_CONFIG["exclude"] = %r[#{Hoe::DEFAULT_CONFIG["exclude"]}|\./bundler/(?!lib|man|exe|[^/]+\.md)|doc/]ox
+Hoe::DEFAULT_CONFIG["exclude"] = %r[#{Hoe::DEFAULT_CONFIG["exclude"]}|\./bundler/(?!lib|man|exe|[^/]+\.md|bundler.gemspec)|doc/]ox
 
 v = hoe.version