update ubi9 ironbank base image to 9.6 (elastic#17802)

Author: jsvd

docker/templates/IronbankDockerfile.erb

@@ -2,7 +2,7 @@
 
 ARG BASE_REGISTRY=registry1.dso.mil
 ARG BASE_IMAGE=ironbank/redhat/ubi/ubi9
-ARG BASE_TAG=9.5
+ARG BASE_TAG=9.6
 ARG LOGSTASH_VERSION=<%= elastic_version %>
 ARG GOLANG_VERSION=1.21.8
 

docker/templates/hardening_manifest.yaml.erb

@@ -14,7 +14,7 @@ tags:
 # Build args passed to Dockerfile ARGs
 args:
   BASE_IMAGE: "redhat/ubi/ubi9"
-  BASE_TAG: "9.5"
+  BASE_TAG: "9.6"
   LOGSTASH_VERSION: "<%= elastic_version %>"
   GOLANG_VERSION: "1.21.8"