Add a configPath option

[sandydoo]

Adds a configPath option to allow changing the path to the generated pre-commit config (.pre-commit-config.yaml by default).

Fixes #345.

Based on #496.

[willfish]

Yay. Thanks for doing this

[zevisert]

Hey @sandydoo thanks for this! I've been annoyed by #345 for a while as well.. As a cachix/devenv user, would this work out of the box with devenv, or does devenv need a PR to enable this? I tried the following in my devenv.nix, but it doesn't seem to be working (no pre-commit configuration is created at .devenv/state/.pre-commit-config.yaml):

{
  config,
  ...
}: {
  git-hooks = {
    configPath = builtins.toPath (config.devenv.state + "/.pre-commit-config.yaml");
    hooks = {
      trim-trailing-whitespace.enable = true;
    };
  };
}

[sandydoo]

@zevisert the path gets prefixed by the git working directory. We should make a note about this until we can support absolute paths as well. You can use a string for now, like ".devenv/state/.pre-commit-config.yaml".

[zevisert]

Ah, that was it - thank you!