Locale/Language in Omnibus Docker

It seems that some of our customers are running into locale/language issues when using the Omnibus Docker image. Example: https://gitlab.zendesk.com/agent/tickets/117559 (internal-only link). This is leading to errors like the following:

Gitlab::Git::CommandError (2:ArgumentError: invalid byte sequence in US-ASCII)

@twk3 pointed out that we fixed this in our cloud native images and suggested that I open an issue here.

Please let me know if you need anything else.