Bump doorkeeper from 5.3.0 to 5.3.1 (#122)

Bumps [doorkeeper](https://github.com/doorkeeper-gem/doorkeeper) from 5.3.0 to 5.3.1.
- [Release notes](https://github.com/doorkeeper-gem/doorkeeper/releases)
- [Changelog](https://github.com/doorkeeper-gem/doorkeeper/blob/master/CHANGELOG.md)
- [Commits](doorkeeper-gem/doorkeeper@v.5.3.0...v.5.3.1)

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

Gemfile

@@ -5,7 +5,7 @@ source "http://rubygems.org"
 ruby "2.6.2"
 
 gem "rails", "~> 6.0"
-gem "doorkeeper", "~> 5.3.0"
+gem "doorkeeper", "~> 5.3.1"
 gem "devise", "~> 4.7"
 
 gem "faker"

Gemfile.lock

@@ -70,7 +70,7 @@ GEM
       responders
       warden (~> 1.2.3)
     diff-lcs (1.3)
-    doorkeeper (5.3.0)
+    doorkeeper (5.3.1)
       railties (>= 5)
     erubi (1.9.0)
     execjs (2.7.0)
@@ -121,7 +121,7 @@ GEM
       pry (>= 0.10.4)
     puma (4.3.1)
       nio4r (~> 2.0)
-    rack (2.1.2)
+    rack (2.2.1)
     rack-test (1.1.0)
       rack (>= 1.0, < 3)
     rack-timeout (0.6.0)
@@ -225,7 +225,7 @@ DEPENDENCIES
   coderay
   database_cleaner
   devise (~> 4.7)
-  doorkeeper (~> 5.3.0)
+  doorkeeper (~> 5.3.1)
   factory_bot_rails
   faker
   jquery-rails