CI: Add zuul.d to irrelevant files

It was ommitted in the patch that renamed it from .zuul.d

Change-Id: I8e4470185321fad1be3e2307c7578ca54d197718
Signed-off-by: Michal Nasiadka <[email protected]>

Author: mnasiadka

zuul.d/base.yaml

@@ -17,7 +17,7 @@
       - ^releasenotes/.*$
       - ^specs/.*$
       - ^test-requirements.txt$
-      - ^\.zuul\.d/
+      - ^zuul\.d/
       - ^\..+
       - ^contrib/
       - ^LICENSE$