Update irrelevant-files to skip run of untouched jobs

Currently when a job config is updated, all other
jobs are triggered unnecessary.

This patch updates irrelevant files to ignore changes
in all job config files except zuul.d/project.yaml(as
this contains the list of jobs to run not their definitions).
With this only the jobs whose definitions are updated(along with
it's child jobs) will be triggered because by default
match-on-config-updates is set to true for a job[1] and
that ignores files or irrelevant-files for a job inclusion.

[1] https://zuul-ci.org/docs/zuul/latest/config/job.html#attr-job.match-on-config-updates

Change-Id: I6ae7891912d9c3dda9349a6e11a1011fd5bc4012
diff --git a/zuul.d/base.yaml b/zuul.d/base.yaml
index bd2ae09..e524c0b 100644
--- a/zuul.d/base.yaml
+++ b/zuul.d/base.yaml
@@ -99,8 +99,7 @@
       - ^tox.ini$
       - ^rally-jobs/.*$
       - ^vagrant/.*$
-      - ^zuul.d/(queens|rocky|stein|train|ussuri)_jobs.yaml$
-      - ^zuul.d/base-nested-switch.yaml$
+      - ^zuul.d/(?!(project)).*\.yaml
 
 - job:
     name: neutron-tempest-plugin-scenario