Install dependencies pip-sync-faster in tox's commands_pre instead of command

[acelaya]

Moving pip-sync-faster execution from tox's commands to commands_pre, so that it gets executed even when commands is overwritten via --run-command.

[seanh]

Thanks! Yeah I think this is already how it works in the cookiecutter so I think this works. Can't immediately see any problems with this. Let's give it a try

[acelaya]

I think this is already how it works in the cookiecutter so I think this works

True! https://github.com/hypothesis/cookiecutters/blob/b8a2828818d884e612a16f59a33ddaf1012dd7ec/_shared/project/tox.ini#L90