Updating golang-github-prometheus-alertmanager-container image to be …

…consistent with ART

Reconciling with https://github.com/openshift/ocp-build-data/tree/e5df10e41b14c724468c8f78e2690f219279bfc4/images/golang-github-prometheus-alertmanager.yml

.ci-operator.yaml

@@ -1,4 +1,4 @@
 build_root_image:
   name: release
   namespace: openshift
-  tag: rhel-8-release-golang-1.20-openshift-4.15
+  tag: rhel-8-release-golang-1.20-openshift-4.16

Dockerfile.ocp

@@ -1,10 +1,10 @@
 # FROM directives are overriden by CI system (both Prow CI and OSBS)
-FROM registry.ci.openshift.org/ocp/builder:rhel-8-golang-1.20-openshift-4.15 AS builder
+FROM registry.ci.openshift.org/ocp/builder:rhel-8-golang-1.20-openshift-4.16 AS builder
 WORKDIR /go/src/github.com/prometheus/alertmanager
 COPY . .
 RUN if yum install -y prometheus-promu; then export BUILD_PROMU=false; fi && make build
 
-FROM registry.ci.openshift.org/ocp/builder:rhel-8-base-openshift-4.15
+FROM registry.ci.openshift.org/ocp/builder:rhel-8-base-openshift-4.16
 LABEL io.k8s.display-name="OpenShift Prometheus Alert Manager" \
       io.k8s.description="Prometheus Alert Manager" \
       io.openshift.tags="prometheus,monitoring" \