Merge branch 'master' into glitch-soc/merge-upstream

Merge branch 'master' into glitch-soc/merge-upstream

Conflicts:
- `config/webpack/shared.js`:
  Upstream has changed how Tesseract.js gets included and dropped a dependency.
  The conflict is caused by glitch-soc having different code due to its
  theming system.
  Ported upstream changes.
- `lib/mastodon/version.rb`:
  Upstream refactor/code style change in a place we replaced upstream's
  repo URL with ours.
  Ported upstram changes, keeping our repo URL.
- `yarn.lock`:
  Upstream dropped dependencies, one of which was textually too close to
  a glitch-soc-specific dependency. Not a real conflict.