Invalidate cache on build change

app/models/ci/build.rb

@@ -313,6 +313,7 @@ module Ci
       build_data = Gitlab::BuildDataBuilder.build(self)
       project.execute_hooks(build_data.dup, :build_hooks)
       project.execute_services(build_data.dup, :build_hooks)
+      project.expire_running_or_pending_build_count
     end
 
     def artifacts?

app/models/project.rb

@@ -1013,8 +1013,12 @@ class Project < ActiveRecord::Base
   end
 
   def running_or_pending_build_count
-    Rails.cache.fetch(['projects', id, 'running_or_pending_build_count'], expires_in: 60) do
+    Rails.cache.fetch(['projects', id, 'running_or_pending_build_count']) do
       builds.running_or_pending.count(:all)
     end
   end
+
+  def expire_running_or_pending_build_count
+    Rails.cache.delete(['projects', id, 'running_or_pending_build_count'])
+  end
 end