Move octavia grenade job on jammy

The current master (2023.2) grenade job is from 2023.1 to
master testing, and tested distro version in 2023.1 is Ubuntu
Jammy. Updating the same in octavia-grenade job.

Change-Id: I8a2c16614f5e603c0940e92bde286195ad65598d

Author: gmaanos

zuul.d/jobs.yaml

@@ -41,7 +41,7 @@
 - job:
     name: octavia-grenade
     parent: grenade
-    nodeset: octavia-single-node-ubuntu-focal
+    nodeset: octavia-single-node-ubuntu-jammy
     required-projects: &o-grenade-required-projects
       - opendev.org/openstack/grenade
       - opendev.org/openstack/octavia