Specify a dummy version for gitlab-backup-cli

What does this MR do?

Specify a dummy version for gitlab-backup-cli. Without a version defined, this will always cauce Git cache to bust, and following components to be rebuilt. For example, see https://dev.gitlab.org/gitlab/omnibus-gitlab/-/jobs/19888482#L772

[Software: gitlab-backup-cli] I | 2024-04-03T20:12:26+00:00 | Forcing a build because resolved version is nil
[Builder: gitlab-backup-cli] I | 2024-04-03T20:12:26+00:00 | Starting build
[Builder: gitlab-backup-cli] I | 2024-04-03T20:12:26+00:00 | mkdir `/opt/gitlab/bin/': 0.0003s
[Builder: gitlab-backup-cli] I | 2024-04-03T20:12:26+00:00 | Rendering `/builds/gitlab/omnibus-gitlab/config/templates/gitlab-backup-cli/gitlab_backup_cli_wrapper.erb' to `/opt/gitlab/bin/gitlab-backup-cli'
/builds/gitlab/omnibus-gitlab/.bundle/local-omnibus/lib/omnibus/templating.rb:39: warning: Passing safe_level with the 2nd argument of ERB.new is deprecated. Do not use it, and specify other arguments as keyword arguments.
[Builder: gitlab-backup-cli] I | 2024-04-03T20:12:26+00:00 | Render erb `gitlab_backup_cli_wrapper.erb': 0.0014s
[Builder: gitlab-backup-cli] I | 2024-04-03T20:12:26+00:00 | Build gitlab-backup-cli: 0.0092s
[Builder: gitlab-backup-cli] I | 2024-04-03T20:12:26+00:00 | Finished build
[Software: gitlab-backup-cli] W | 2024-04-03T20:12:26+00:00 | No version given! Git caching disabled.
[GitCache: gitlab-backup-cli] I | 2024-04-03T20:12:26+00:00 | Looking for cache tag: gitlab-backup-cli-0a05db9d2399dde316695f095abf41f5d2a93282751ff11ec9370c43dc91d0e6-3
[GitCache: gitlab-backup-cli] I | 2024-04-03T20:12:26+00:00 | Created cache tag: gitlab-backup-cli-0a05db9d2399dde316695f095abf41f5d2a93282751ff11ec9370c43dc91d0e6-3
[Software: gitlab-backup-cli] I | 2024-04-03T20:12:26+00:00 | Dirtied the cache
[Software: gitlab-redis-cli] I | 2024-04-03T20:12:26+00:00 | Building because `gitlab-backup-cli' dirtied the cache

Related issues

#8476 (closed)

Checklist

See Definition of done.

For anything in this list which will not be completed, please provide a reason in the MR discussion.

Required

• MR title and description are up to date, accurate, and descriptive.
• MR targeting the appropriate branch.
• Latest Merge Result pipeline is green.
• When ready for review, MR is labeled "~workflow::ready for review" per the Distribution MR workflow.

For GitLab team members

If you don't have access to this, the reviewer should trigger these jobs for you during the review process.

• The manual Trigger:ee-package jobs have a green pipeline running against latest commit.
• If config/software or config/patches directories are changed, make sure the build-package-on-all-os job within the Trigger:ee-package downstream pipeline succeeded.
• If you are changing anything SSL related, then the Trigger:package:fips manual job within the Trigger:ee-package downstream pipeline must succeed.
• If CI configuration is changed, the branch must be pushed to dev.gitlab.org to confirm regular branch builds aren't broken.

Expected (please provide an explanation if not completing)

• Test plan indicating conditions for success has been posted and passes.
• Documentation created/updated.
• Tests added.
• Integration tests added to GitLab QA.
• Equivalent MR/issue for the GitLab Chart opened.
• Validate potential values for new configuration settings. Formats such as integer 10, duration 10s, URI scheme://user:passwd@host:port may require quotation or other special handling when rendered in a template and written to a configuration file.