Bump doorkeeper from 5.3.3 to 5.4.0 (#13733)

* Bump doorkeeper from 5.3.3 to 5.4.0

Bumps [doorkeeper](https://github.com/doorkeeper-gem/doorkeeper) from 5.3.3 to 5.4.0.
- [Release notes](https://github.com/doorkeeper-gem/doorkeeper/releases)
- [Changelog](https://github.com/doorkeeper-gem/doorkeeper/blob/master/CHANGELOG.md)
- [Commits](https://github.com/doorkeeper-gem/doorkeeper/compare/v5.3.3...v5.4.0)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

* Fix tests

* Fix use of Doorkeeper::AccessToken.find_or_create_for

* Fix tests?

Co-authored-by: dependabot-preview[bot] <27856297+dependabot-preview[bot]@users.noreply.github.com>
Co-authored-by: Thibaut Girka <thib@sitedethib.com>

Gemfile

@@ -49,7 +49,7 @@ gem 'omniauth-saml', '~> 1.10'
 gem 'omniauth', '~> 1.9'
 
 gem 'discard', '~> 1.2'
-gem 'doorkeeper', '~> 5.3'
+gem 'doorkeeper', '~> 5.4'
 gem 'fast_blank', '~> 1.0'
 gem 'fastimage'
 gem 'goldfinger', '~> 2.1'