Request for new parameter to set user-defined directory

## Description:

I would like to request the addition of a new parameter for the program, specifically for setting the directory to a user-defined directory. This would allow users to specify the location to fetch the files rather than being limited to the default directory `\tmp`. The location should default to `/tmp` if the user does not specify a location.

Reference:
https://github.com/nexB/fetchcode/blob/master/src/fetchcode/vcs/git.py#L39
https://github.com/nexB/fetchcode/blob/master/src/fetchcode/vcs/__init__.py#L70

The new parameter could be named directory and would be used like so: `fetch_via_git/vcs(url, directory="/path/to/directory")`

I believe this feature would greatly improve the flexibility and usability of the program for many users. Please let me know if there is any additional information that you need from me. Thank you for your consideration.