Customize "Release" page og:description meta tag

This commit updates the dedicated "Release" page to use the release's
description as the og:description meta tag's content instead of the
default (the project's description).

app/views/projects/releases/show.html.haml

 - add_to_breadcrumbs _("Releases"), project_releases_path(@project)
 - page_title @release.name
+- page_description @release.description_html
 
 #js-show-release-page{ data: { project_id: @project.id, tag_name: @release.tag } }

changelogs/unreleased/nfriend-add-release-og-description.yml

+---
+title: Add og:description meta tag to individual "Release" page
+merge_request: 42889
+author:
+type: added

spec/features/projects/releases/user_views_release_spec.rb

@@ -4,17 +4,25 @@ require 'spec_helper'
 
 RSpec.describe 'User views Release', :js do
   let(:project) { create(:project, :repository) }
-  let(:release) { create(:release, project: project, name: 'The first release' ) }
   let(:user) { create(:user) }
 
+  let(:release) do
+    create(:release,
+           project: project,
+           name: 'The first release',
+           description: '**Lorem** _ipsum_ dolor sit [amet](https://example.com)')
+  end
+
   before do
     project.add_developer(user)
 
-    gitlab_sign_in(user)
+    sign_in(user)
 
     visit project_release_path(project, release)
   end
 
+  it_behaves_like 'page meta description', 'Lorem ipsum dolor sit amet'
+
   it 'renders the breadcrumbs' do
     within('.breadcrumbs') do
       expect(page).to have_content("#{project.creator.name} #{project.name} Releases #{release.name}")
@@ -31,7 +39,7 @@ RSpec.describe 'User views Release', :js do
       expect(page).to have_content(release.name)
       expect(page).to have_content(release.tag)
       expect(page).to have_content(release.commit.short_id)
-      expect(page).to have_content(release.description)
+      expect(page).to have_content('Lorem ipsum dolor sit amet')
     end
   end
 end