Add boilerplate image-v8.3.6 to Prow mirroring (#78944)

Adds boilerplate:image-v8.3.6 to supplementalCIImages for Prow mirroring.

This image includes:
- UBI9:9.7-1778044007 with Go 1.25.9
- Fixes for critical stdlib CVEs (CVE-2026-27143 and 11 others)

Required for downstream projects (aws-account-operator and others) to
pass CI coverage tests with Go 1.25.9 security fixes.

Related: openshift/boilerplate#727
Related: openshift/aws-account-operator#979

Author: BATMAN-JD

core-services/image-mirroring/_config.yaml

@@ -27,6 +27,8 @@ supplementalCIImages:
     image: quay.io/redhat-services-prod/openshift/boilerplate:image-v8.3.4
   openshift/boilerplate:image-v8.3.5:
     image: quay.io/redhat-services-prod/openshift/boilerplate:image-v8.3.5
+  openshift/boilerplate:image-v8.3.6:
+    image: quay.io/redhat-services-prod/openshift/boilerplate:image-v8.3.6
   azure/plugin-base:latest:
     image: registry.access.redhat.com/rhel7:latest
   chaos/krkn:latest: