Mirror mariadb:10.11 to quay

This is the mariadb version that we are primarily using in opendev at
the moment. Mirroring it to quay should allow us to start fetching the
image from quay to avoid docker hub rate limits.

Change-Id: Ic19fd98a51156cea23569ee27a92489c0002363f

zuul.d/docker-mirror.yaml

@@ -102,6 +102,11 @@
           dest_repository: quay.io/opendevmirror/mariadb
           dest_tag: latest
           dest_registry: quay.io
+        - src_repository: docker.io/library/mariadb
+          src_tag: '10.11'
+          dest_repository: quay.io/opendevmirror/mariadb
+          dest_tag: '10.11'
+          dest_registry: quay.io
 
 - job:
     name: opendev-mirror-container-image-node