Execute build hooks on pending status

Run build hooks (webhooks and integrations) when
a build changes status to pending.

Changelog: added

app/models/ci/build.rb

@@ -288,6 +288,7 @@ module Ci
 
         build.run_after_commit do
           BuildQueueWorker.perform_async(id)
+          BuildHooksWorker.perform_async(id)
         end
       end
 

spec/models/ci/build_spec.rb

@@ -3762,6 +3762,12 @@ RSpec.describe Ci::Build do
 
       build.enqueue
     end
+
+    it 'queues BuildHooksWorker' do
+      expect(BuildHooksWorker).to receive(:perform_async).with(build.id)
+
+      build.enqueue
+    end
   end
 
   describe 'state transition: pending: :running' do