Begin testing on Ubuntu 22.04 LTS

Author: mark-vieira

.ci/jobs.t/elastic+elasticsearch+multijob+platform-support-unix.yml

@@ -26,6 +26,7 @@
             - "sles-15&&immutable"
             - "ubuntu-18.04&&immutable"
             - "ubuntu-20.04&&immutable"
+            - "ubuntu-22.04&&immutable"
             - "rocky-linux-8&&immutable"
             - "rhel-7&&immutable"
             - "rhel-8&&immutable"