Refactor labels to badges (#3503)

From the migrations documentation of Bootstrap v4 -> v5:

> - Consolidated .label and .badge to disambiguate from the <label> element and simplify related components.

This change refactors the usage of labels to their counterparts as badges. Namely the logout label/badge and the representation of booleans. The label classes currently referenced no longer exist.

app/views/layouts/rails_admin/_secondary_navigation.html.erb

@@ -17,7 +17,9 @@
     <% end %>
     <% if logout_path.present? %>
       <li class="nav-item">
-        <%= link_to t('admin.misc.log_out'), logout_path, method: logout_method, class: 'nav-link label label-danger', data: {turbo: 'false'} %>
+        <%= link_to logout_path, method: logout_method, class: 'nav-link', data: {turbo: 'false'} do %>
+          <span class="badge bg-danger"><%= t('admin.misc.log_out') %></span>
+        <% end %>
       </li>
     <% end %>
   <% end %>

lib/rails_admin/config/fields/types/boolean.rb

@@ -33,7 +33,7 @@ class Boolean < RailsAdmin::Config::Fields::Base
           end
 
           register_instance_option :pretty_value do
-            %(<span class="label label-#{css_classes[form_value]}">#{labels[form_value]}</span>).html_safe
+            %(<span class="badge bg-#{css_classes[form_value]}">#{labels[form_value]}</span>).html_safe
           end
 
           register_instance_option :export_value do

spec/integration/rails_admin_spec.rb

@@ -110,9 +110,9 @@
       is_expected.to have_content 'Log out'
     end
 
-    it 'has label-danger class on log out link' do
+    it 'has bg-danger class on log out link' do
       visit dashboard_path
-      is_expected.to have_selector('.label-danger')
+      is_expected.to have_selector('.bg-danger')
     end
 
     it 'has links for actions which are marked as show_in_navigation' do

spec/rails_admin/config/fields/types/boolean_spec.rb

@@ -13,9 +13,9 @@
 
   describe '#pretty_value' do
     {
-      false => %(<span class="label label-danger"><span class="fas fa-times"></span></span>),
-      true => %(<span class="label label-success"><span class="fas fa-check"></span></span>),
-      nil => %(<span class="label label-default"><span class="fas fa-minus"></span></span>),
+      false => %(<span class="badge bg-danger"><span class="fas fa-times"></span></span>),
+      true => %(<span class="badge bg-success"><span class="fas fa-check"></span></span>),
+      nil => %(<span class="badge bg-default"><span class="fas fa-minus"></span></span>),
     }.each do |field_value, expected_result|
       context "when field value is '#{field_value.inspect}'" do
         let(:test_object) { FieldTest.new(boolean_field: field_value) }