Bump rails_admin from 2.2.1 to 3.1.0

Bumps [rails_admin](https://github.com/sferik/rails_admin) from 2.2.1 to 3.1.0.
- [Release notes](https://github.com/sferik/rails_admin/releases)
- [Changelog](https://github.com/railsadminteam/rails_admin/blob/master/CHANGELOG.md)
- [Commits](https://github.com/sferik/rails_admin/compare/v2.2.1...v3.1.0)

---
updated-dependencies:
- dependency-name: rails_admin
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Gemfile

@@ -35,7 +35,7 @@ gem 'pry-byebug'
 gem 'puma'
 gem 'pundit'
 gem 'rails', '~> 6.1.7'
-gem 'rails_admin', '< 3.0.0' # Blocked by https://github.com/railsadminteam/rails_admin/issues/3490
+gem 'rails_admin', '< 4.0.0'
 gem 'rails-i18n'
 gem 'rails-timeago'
 gem 'ransack'

Gemfile.lock

@@ -166,9 +166,6 @@ GEM
     glob (0.3.1)
     globalid (1.0.0)
       activesupport (>= 5.0)
-    haml (5.2.2)
-      temple (>= 0.8.0)
-      tilt
     hana (1.3.7)
     hashdiff (1.0.1)
     hashie (5.0.0)
@@ -192,12 +189,6 @@ GEM
     jbuilder (2.11.5)
       actionview (>= 5.0.0)
       activesupport (>= 5.0.0)
-    jquery-rails (4.5.1)
-      rails-dom-testing (>= 1, < 3)
-      railties (>= 4.2.0)
-      thor (>= 0.14, < 2.0)
-    jquery-ui-rails (6.0.1)
-      railties (>= 3.2.16)
     js-routes (2.2.4)
       railties (>= 4)
     json (2.6.2)
@@ -309,9 +300,6 @@ GEM
     rack (2.2.4)
     rack-mini-profiler (3.0.0)
       rack (>= 1.2.0)
-    rack-pjax (1.1.0)
-      nokogiri (~> 1.5)
-      rack (>= 1.1)
     rack-proxy (0.7.4)
       rack
     rack-test (2.0.2)
@@ -346,18 +334,12 @@ GEM
     rails-timeago (2.20.0)
       actionpack (>= 5.2)
       activesupport (>= 5.2)
-    rails_admin (2.2.1)
+    rails_admin (3.1.0)
       activemodel-serializers-xml (>= 1.0)
-      builder (~> 3.1)
-      haml (>= 4.0, < 6)
-      jquery-rails (>= 3.0, < 5)
-      jquery-ui-rails (>= 5.0, < 7)
       kaminari (>= 0.14, < 2.0)
       nested_form (~> 0.3)
-      rack-pjax (>= 0.7)
+      rails (>= 6.0, < 8)
-      rails (>= 5.0, < 7)
+      turbo-rails (~> 1.0)
-      remotipart (~> 1.3)
-      sassc-rails (>= 1.3, < 3)
     railties (6.1.7)
       actionpack (= 6.1.7)
       activesupport (= 6.1.7)
@@ -375,7 +357,6 @@ GEM
       ffi (~> 1.0)
     rbtree (0.4.5)
     regexp_parser (2.6.1)
-    remotipart (1.4.4)
     rest-client (2.1.0)
       http-accept (>= 1.7.0, < 2.0)
       http-cookie (>= 1.0.2, < 2.0)
@@ -507,6 +488,10 @@ GEM
     tubesock (0.2.9)
       rack (>= 1.5.0)
       websocket (>= 1.1.0)
+    turbo-rails (1.3.2)
+      actionpack (>= 6.0.0)
+      activejob (>= 6.0.0)
+      railties (>= 6.0.0)
     turbolinks (5.2.1)
       turbolinks-source (~> 5.2)
     turbolinks-source (5.2.0)
@@ -594,7 +579,7 @@ DEPENDENCIES
   rails-controller-testing
   rails-i18n
   rails-timeago
-  rails_admin (< 3.0.0)
+  rails_admin (< 4.0.0)
   ransack
   rest-client
   rspec-autotest

config/initializers/rails_admin.rb

@@ -1,6 +1,7 @@
 # frozen_string_literal: true
 
 RailsAdmin.config do |config|
+  config.asset_source = :sprockets
   ### Popular gems integration
 
   ## == Devise ==