Make stable/ussuri job voting

stable/ussuri job was made non voting due to
bug#1959467

- https://review.opendev.org/c/openstack/tempest/+/827258

As bug is fixed now, let's revert it to voting again.

Change-Id: I834300ee8d9ee8952284b55f53d97456a1ca6032
diff --git a/zuul.d/project.yaml b/zuul.d/project.yaml
index 2d4f10a..731a72a 100644
--- a/zuul.d/project.yaml
+++ b/zuul.d/project.yaml
@@ -42,7 +42,6 @@
         - tempest-full-victoria-py3:
             irrelevant-files: *tempest-irrelevant-files
         - tempest-full-ussuri-py3:
-            voting: false
             irrelevant-files: *tempest-irrelevant-files
         - tempest-multinode-full-py3:
             irrelevant-files: *tempest-irrelevant-files