Move queue declaration to project level

This moves the watcher queue declaration from the pipeline level
(where it is no longer valid) to the project level.

https: //lists.openstack.org/pipermail/openstack-discuss/2022-May/028603.html
Change-Id: I06923abb00f7eecd59587f44cd1f6a069e88a9fc
(cherry picked from commit 6003322711)

.zuul.yaml

@@ -1,4 +1,5 @@
 - project:
+    queue: watcher
     templates:
       - check-requirements
       - openstack-cover-jobs
@@ -17,7 +18,6 @@
         - watcher-tls-test
         - watcher-tempest-functional-ipv6-only
     gate:
-      queue: watcher
       jobs:
         - watcher-tempest-functional
         - watcher-tempest-functional-ipv6-only