Add redirect for project tags page

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

config/routes/project.rb

@@ -482,7 +482,7 @@ constraints(::Constraints::ProjectUrlConstrainer.new) do
       # Legacy routes.
       # Introduced in 12.0.
       # Should be removed with https://gitlab.com/gitlab-org/gitlab/issues/28848.
-      Gitlab::Routing.redirect_legacy_paths(self, :mirror,
+      Gitlab::Routing.redirect_legacy_paths(self, :mirror, :tags,
                                             :cycle_analytics, :mattermost, :variables, :triggers,
                                             :environments, :protected_environments, :error_tracking, :alert_management,
                                             :serverless, :clusters, :audit_events, :wikis, :merge_requests,

spec/routing/project_routing_spec.rb

@@ -230,6 +230,8 @@ describe 'project routing' do
       expect(delete('/gitlab/gitlabhq/-/tags/feature%2B45/foo/bar/baz')).to route_to('projects/tags#destroy', namespace_id: 'gitlab', project_id: 'gitlabhq', id: 'feature+45/foo/bar/baz')
       expect(delete('/gitlab/gitlabhq/-/tags/feature@45/foo/bar/baz')).to route_to('projects/tags#destroy', namespace_id: 'gitlab', project_id: 'gitlabhq', id: 'feature@45/foo/bar/baz')
     end
+
+    it_behaves_like 'redirecting a legacy project path', "/gitlab/gitlabhq/tags", "/gitlab/gitlabhq/-/tags"
   end
 
   #     project_deploy_keys GET    /:project_id/deploy_keys(.:format)          deploy_keys#index