Add irrelevant files to .zuul.yaml

This commit adds 4 irrelevant files to both "irrelevant-files" and
"irrelevant-files-2". We don't need to run tempest tests with updating
such files because they don't affect tempest tests.

Change-Id: I6f84abc1b9273f38b99678edaff54deb0fd99e0c

.zuul.yaml

@@ -613,6 +613,10 @@
               - ^tempest/hacking/.*$
               - ^tempest/tests/.*$
               - ^tools/.*$
+              - ^.coveragerc$
+              - ^.gitignore$
+              - ^.gitreview$
+              - ^.mailmap$
         - tempest-full-py3:
             irrelevant-files: *tempest-irrelevant-files
         - tempest-full-py3-ipv6:
@@ -643,6 +647,10 @@
               - ^setup.cfg$
               - ^tempest/hacking/.*$
               - ^tempest/tests/.*$
+              - ^.coveragerc$
+              - ^.gitignore$
+              - ^.gitreview$
+              - ^.mailmap$
               # tools/ is not here since this relies on a script in tools/.
         - tempest-ipv6-only:
             irrelevant-files: *tempest-irrelevant-files-2