Feature Request

Description

When someone upgrades from a pre 2.0 version, they can encounter an error where guet hooks complain that they can't work. Usually, it comes from the fact that the hook has a python shebang instead of a python3 shebang.

Ideally some of the commands would check if the hooks are malformed and throw an error.

Example

$ guet set initials1 initials2
Your guet hooks are incorrectly formatted. Please use guet start to recreate them.