Switch default nodeset to ubuntu-jammy

As announced[*], we are moving from ubuntu-focal to ubuntu-jammy as
our default nodeset. Any jobs which don't specify a nodeset will
inherit this change in default value.

[*] https://lists.opendev.org/pipermail/service-announce/2022-October/000047.html

Change-Id: I6b349a19b4dee397c1928c24eab9647e7c9aec30

zuul.d/jobs.yaml

@@ -58,7 +58,7 @@
       - zuul: zuul/zuul-jobs
     timeout: 1800
     post-timeout: 1800
-    nodeset: ubuntu-focal
+    nodeset: ubuntu-jammy
     secrets: &log_clouds
       - opendev_cloud_ovh_bhs
       - opendev_cloud_ovh_gra
@@ -85,7 +85,7 @@
       - zuul: zuul/zuul-jobs
     timeout: 1800
     post-timeout: 1800
-    nodeset: ubuntu-focal
+    nodeset: ubuntu-jammy
     secrets: *log_clouds
 
 - job:
@@ -112,7 +112,7 @@
     timeout: 1800
     post-timeout: 1800
     allowed-projects: zuul/zuul-jobs
-    nodeset: ubuntu-focal
+    nodeset: ubuntu-jammy
     secrets: *log_clouds
 
 - secret: