Merge commit 'e0648a916ab81925545504173bf4f43ec64d4f3c' into glitch-soc/merge-upstream

Conflicts:
- `app/models/custom_emoji.rb`:
  An upstream refactor touched lines adjacent to ones modified in glitch-soc.
  Ported upstream's changes.

lib/mastodon/version.rb

@@ -43,6 +43,12 @@ module Mastodon
       @gem_version ||= Gem::Version.new(to_s.split('+')[0])
     end
 
+    def api_versions
+      {
+        mastodon: 2,
+      }
+    end
+
     def repository
       ENV.fetch('GITHUB_REPOSITORY', 'glitch-soc/mastodon')
     end