Skip unit/functional tests on pre-commit config update

Number of repositories have introduced pre-commit for code style check.
Skip unit tests and functional tests for its config file because
the config file has no impact on functionality.

Change-Id: I0c6a41ab36d69ed767e99eaa87a555a3a940a573

zuul.d/jobs.yaml

@@ -74,6 +74,7 @@
       - ^doc/.*$
       - ^releasenotes/.*$
       - ^deliverables/.*$
+      - ^\.pre-commit-config\.yaml$
     vars:
       tox_envlist: py27
       bindep_profile: test py27