Expand gem metadata urls

[brettchalupa]

https://guides.rubygems.org/specification-reference/#metadata=

s.metadata = {
  "bug_tracker_uri"   => "https://example.com/user/bestgemever/issues",
  "changelog_uri"     => "https://example.com/user/bestgemever/CHANGELOG.md",
  "documentation_uri" => "https://www.example.info/gems/bestgemever/0.0.1",
  "homepage_uri"      => "https://bestgemever.example.io",
  "mailing_list_uri"  => "https://groups.example.com/bestgemever",
  "source_code_uri"   => "https://example.com/user/bestgemever",
  "wiki_uri"          => "https://example.com/user/bestgemever/wiki"
  "funding_uri"       => "https://example.com/donate"
}