Bump doorkeeper from 5.5.4 to 5.6.0 (#19163)

Bumps [doorkeeper](https://github.com/doorkeeper-gem/doorkeeper) from 5.5.4 to 5.6.0.
- [Release notes](https://github.com/doorkeeper-gem/doorkeeper/releases)
- [Changelog](https://github.com/doorkeeper-gem/doorkeeper/blob/main/CHANGELOG.md)
- [Commits](https://github.com/doorkeeper-gem/doorkeeper/compare/v5.5.4...v5.6.0

)

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

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

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

Gemfile

@@ -46,7 +46,7 @@ gem 'omniauth-rails_csrf_protection', '~> 0.1'
 
 gem 'color_diff', '~> 0.1'
 gem 'discard', '~> 1.2'
-gem 'doorkeeper', '~> 5.5'
+gem 'doorkeeper', '~> 5.6'
 gem 'ed25519', '~> 1.3'
 gem 'fast_blank', '~> 1.0'
 gem 'fastimage'

Gemfile.lock

@@ -207,7 +207,7 @@ GEM
     docile (1.3.4)
     domain_name (0.5.20190701)
       unf (>= 0.0.5, < 1.0.0)
-    doorkeeper (5.5.4)
+    doorkeeper (5.6.0)
       railties (>= 5)
     dotenv (2.8.1)
     dotenv-rails (2.8.1)
@@ -761,7 +761,7 @@ DEPENDENCIES
   devise-two-factor (~> 4.0)
   devise_pam_authenticatable2 (~> 9.2)
   discard (~> 1.2)
-  doorkeeper (~> 5.5)
+  doorkeeper (~> 5.6)
   dotenv-rails (~> 2.8)
   ed25519 (~> 1.3)
   fabrication (~> 2.30)