Add tap-as-a-service API tests

As tap-as-a-service was moved under Neutron governance its tests should
be in neutron-tempest-plugin.

Change-Id: I01dd33e0610e1db13815ea153b5c2299d8699d30
diff --git a/zuul.d/project.yaml b/zuul.d/project.yaml
index 08fb58c..031860f 100644
--- a/zuul.d/project.yaml
+++ b/zuul.d/project.yaml
@@ -186,6 +186,7 @@
         - neutron-tempest-plugin-vpnaas-ussuri
         - neutron-tempest-plugin-vpnaas-victoria
         - neutron-tempest-plugin-vpnaas-wallaby
+        - neutron-tempest-plugin-tap-as-a-service
 
     gate:
       jobs: