[8.5] [artifacts] Bump ironbank base image to ubi:8.7 (#146917) (#146935

)

# Backport

This will backport the following commits from `main` to `8.5`:
- [[artifacts] Bump ironbank base image to ubi:8.7
(#146917)](#146917)

<!--- Backport version: 8.9.7 -->

### Questions ?
Please refer to the [Backport tool
documentation](https://github.com/sqren/backport)

<!--BACKPORT [{"author":{"name":"Jonathan
Budzenski","email":"[email protected]"},"sourceCommit":{"committedDate":"2022-12-02T22:44:37Z","message":"[artifacts]
Bump ironbank base image to ubi:8.7
(#146917)","sha":"939698faf048328656417a3762a4391baf1e1ab8","branchLabelMapping":{"^v8.7.0$":"main","^v(\\d+).(\\d+).\\d+$":"$1.$2"}},"sourcePullRequest":{"labels":["Team:Operations","release_note:skip","v8.6.0","v7.17.8","v8.7.0","v8.5.3"],"number":146917,"url":"https://github.com/elastic/kibana/pull/146917","mergeCommit":{"message":"[artifacts]
Bump ironbank base image to ubi:8.7
(#146917)","sha":"939698faf048328656417a3762a4391baf1e1ab8"}},"sourceBranch":"main","suggestedTargetBranches":["8.6","7.17","8.5"],"targetPullRequestStates":[{"branch":"8.6","label":"v8.6.0","labelRegex":"^v(\\d+).(\\d+).\\d+$","isSourceBranch":false,"state":"NOT_CREATED"},{"branch":"7.17","label":"v7.17.8","labelRegex":"^v(\\d+).(\\d+).\\d+$","isSourceBranch":false,"state":"NOT_CREATED"},{"branch":"main","label":"v8.7.0","labelRegex":"^v8.7.0$","isSourceBranch":true,"state":"MERGED","url":"https://github.com/elastic/kibana/pull/146917","number":146917,"mergeCommit":{"message":"[artifacts]
Bump ironbank base image to ubi:8.7
(#146917)","sha":"939698faf048328656417a3762a4391baf1e1ab8"}},{"branch":"8.5","label":"v8.5.3","labelRegex":"^v(\\d+).(\\d+).\\d+$","isSourceBranch":false,"state":"NOT_CREATED"}]}]
BACKPORT-->

Co-authored-by: Jonathan Budzenski <[email protected]>

src/dev/build/tasks/os_packages/docker_generator/templates/ironbank/Dockerfile

@@ -4,7 +4,7 @@
 ################################################################################
 ARG BASE_REGISTRY=registry1.dso.mil
 ARG BASE_IMAGE=redhat/ubi/ubi8
-ARG BASE_TAG=8.6
+ARG BASE_TAG=8.7
 
 FROM ${BASE_REGISTRY}/${BASE_IMAGE}:${BASE_TAG} as prep_files