Update upstream buildah required status checks (openshift#48909)

Third-party CI systems are in use by upstream buildah.  Some of which
will post status that is required for PRs to merge safely, other
statuses should be left up to human-operators to pontificate.

For all buildah branches, prow should not manage branch-protection,
but it should block PR merging based on the Cirrus-CI
success-aggregation task "Total Success" as per:
https://docs.ci.openshift.org/docs/architecture/branch-protection

Signed-off-by: Chris Evich <[email protected]>

Author: cevich

core-services/prow/02_config/_config.yaml

@@ -393,6 +393,10 @@ tide:
         repos:
           aardvark-dns:
             skip-unknown-contexts: true
+          buildah:
+            required-contexts:
+            - Total Success
+            skip-unknown-contexts: true
           common:
             skip-unknown-contexts: true
           dnsname: