On non-NixOS configs, `git` has been complaining about missing `--global`
variables for `user` and `email`.
TODO(wpcarro): Support this in google-briefcase instead.
Change-Id: Iae29fe9aaa6c13295063137f241eeb5861d4b244
Reviewed-on: https://cl.tvl.fyi/c/depot/+/4792
Tested-by: BuildkiteCI
Reviewed-by: wpcarro <wpcarro@gmail.com>
Autosubmit: wpcarro <wpcarro@gmail.com>
