Bump doorkeeper from 5.5.2 to 5.5.3 (mastodon#16778)

Bumps [doorkeeper](https://github.com/doorkeeper-gem/doorkeeper) from 5.5.2 to 5.5.3.
- [Release notes](https://github.com/doorkeeper-gem/doorkeeper/releases)
- [Changelog](https://github.com/doorkeeper-gem/doorkeeper/blob/main/CHANGELOG.md)
- [Commits](doorkeeper-gem/doorkeeper@v5.5.2...v5.5.3)

---
updated-dependencies:
- dependency-name: doorkeeper
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Gemfile.lock

@@ -188,7 +188,7 @@ GEM
  docile (1.3.4)
  domain_name (0.5.20190701)
  unf (>= 0.0.5, < 1.0.0)
- doorkeeper (5.5.2)
+ doorkeeper (5.5.3)
  railties (>= 5)
  dotenv (2.7.6)
  dotenv-rails (2.7.6)