Fix required extensions for the subnet's service type API tests

In [1] new tests for subnet service types were added but by mistake
'service-types' was set as API extension required for those tests.
In fact this API feature in the subnet is provided by the
'subnet-service-types' extension and this should be required for that
tests.

This patch also adds "subnet-service-types" extension to the Tempest
conf in jobs for all branches up to stable/queens becuase this API
extension was available in Neutron since queens for sure so it's safe to
add it there.

[1] https://review.opendev.org/c/openstack/neutron-tempest-plugin/+/787718

Related-Bug: #1933115
Change-Id: I2b9b472a07455f5e67fc4adcc3b264b4ad8a9dbf
diff --git a/zuul.d/queens_jobs.yaml b/zuul.d/queens_jobs.yaml
index 33430c8..9701548 100644
--- a/zuul.d/queens_jobs.yaml
+++ b/zuul.d/queens_jobs.yaml
@@ -75,6 +75,7 @@
         - standard-attr-timestamp
         - standard-attr-tag
         - subnet_allocation
+        - subnet-service-types
         - trunk
         - trunk-details
       network_api_extensions_tempest: