Update Gitlab::JsonCache to add Gitlab.revision to the cache_key by
default instead of using Gitlab::VERSION and Rails.version. This change
will result to broadcast messages (and anything that uses JsonCache
going forward) cache invalidation on every deploy which should prevent
the stale data issue encountered in
https://gitlab.com/gitlab-com/gl-infra/production/-/issues/6372.

For backwards compatibility, Gitlab::JsonCache accepts
{ cache_key_strategy: :version } (adds Gitlab::VERSION and
Rails.version to the cache_key) which will invalidate the cache on every
bump of Gitlab::VERSION (every release, once a month) and Rails.version.

Changelog: changed