Ingress NGINX: Promote Custom Error Pages v1.1.1.

Commit: kubernetes/ingress-nginx@b932ac0
Job: https://prow.k8s.io/view/gs/kubernetes-ci-logs/logs/post-ingress-nginx-custom-error-pages/1878552007782961152
Build: https://storage.googleapis.com/kubernetes-ci-logs/logs/post-ingress-nginx-custom-error-pages/1878552007782961152/artifacts/build.log

Author: Gacko

registry.k8s.io/images/k8s-staging-ingress-nginx/images.yaml

@@ -143,6 +143,7 @@
     "sha256:d8ab7de384cf41bdaa696354e19f1d0efbb0c9ac69f8682ffc0cc008a252eb76": ["v1.0.1"]
     "sha256:b2259cf6bfda813548a64bded551b1854cb600c4f095738b49b4c5cdf8ab9d21": ["v1.0.2"]
     "sha256:a2342e403fc3c19f81f5625e1b93daa0f8fb3dfaa1df4905f85e32d2d98a5e96": ["v1.1.0"]
+    "sha256:8c10776191ae44b5c387b8c7696d8bc17ceec90d7184a3a38b89ac8434b6c56b": ["v1.1.1"]
 
 # Ingress NGINX: E2E Test Echo
 - name: e2e-test-echo