Add list of pending releases directly in mail notifications for version updates (#29436)

app/mailers/admin_mailer.rb

@@ -46,12 +46,16 @@ class AdminMailer < ApplicationMailer
   end
 
   def new_software_updates
+    @software_updates = SoftwareUpdate.all.to_a.sort_by(&:gem_version)
+
     locale_for_account(@me) do
       mail subject: default_i18n_subject(instance: @instance)
     end
   end
 
   def new_critical_software_updates
+    @software_updates = SoftwareUpdate.where(urgent: true).to_a.sort_by(&:gem_version)
+
     headers['Priority'] = 'urgent'
     headers['X-Priority'] = '1'
     headers['Importance'] = 'high'

app/views/admin_mailer/new_critical_software_updates.text.erb

@@ -1,3 +1,7 @@
 <%= raw t('admin_mailer.new_critical_software_updates.body') %>
 
+<% @software_updates.each do |update| %>
+- Mastodon #{update.version}: #{update.release_notes}
+<% end %>
+
 <%= raw t('application_mailer.view')%> <%= admin_software_updates_url %>

app/views/admin_mailer/new_software_updates.text.erb

@@ -1,3 +1,7 @@
 <%= raw t('admin_mailer.new_software_updates.body') %>
 
+<% @software_updates.each do |update| %>
+- Mastodon #{update.version}: #{update.release_notes}
+<% end %>
+
 <%= raw t('application_mailer.view')%> <%= admin_software_updates_url %>