Setting bats repository in values.yaml

[jlknoch]

Hey,

we want to use the Mattermost Team Edition by using the helm chart. Our cluster runs in an air-gapped environment so we have to use out own docker image repository.

We already deployed a first version and we were able to set the repository for the mattermost image, curl and mysql. It wasn't possible to set a repository for bats. It would help us alot if you could add this option to the values.yaml.

Have a nice day & best regards
Jan-Lukas