Re-compile when config changes

We need to work out how to re-compile the pre_commit task when the config changes.

Example:
A user sets up pre_commit for a project with just `test` in the config.
The next day, the user adds `credo --strict` to the config, but the pre_commit doesn't update :cry:

Currently the only way to force an update is to delete the build folder and recompile.

Start by tracing the pre_commit task and how it reads the project config and build folder. Confirm the current behavior with a config change, then verify that the task recompiles or refreshes its generated hook without requiring the build folder to be deleted.

Written by the indexing model from the issue text.