CI: Removing ironic job queue

Please see:
https://zuul-ci.org/docs/zuul/latest/releasenotes.html#relnotes-4-1-0-deprecation-notes

Change-Id: Ic032ed05951f2e0f8f584d31a35ec4bb12846b06
diff --git a/zuul.d/project.yaml b/zuul.d/project.yaml
index 6198ffd..702a1f4 100644
--- a/zuul.d/project.yaml
+++ b/zuul.d/project.yaml
@@ -46,7 +46,6 @@
         - ironic-inspector-tempest-discovery-victoria:
             voting: false
     gate:
-      queue: ironic
       jobs:
         - ironic-standalone
         - ironic-standalone-xena