[Scripts] Pass original working directory as env variable

[Bubichoo-Teitichoo]

Is your feature/enhancement proposal related to a problem? Please describe.

Coming from Poetry + Poe I'm missing the ability read/use the working directory of the calling shell within my scripts.
Especially with mono-repos I may need the actual working directory of the shell to properly do some scripted actions in a particular part of the repo.

Describe the solution you'd like

The solution to the problem would be rather simple. Somewhere in TaskRunner._run_process you would just have to create a environment variable that holds the current working directory. e.g.

os.environ["PDM_PWD"] = str(Path.cwd())

For naming I'd propose something similar to what Poe is doing: https://poethepoet.natn.io/env_vars.html

I'm happy to make the relevant changes and create a PR if you think this proposal is good.

[frostming]

I'd suggest PDM_RUN_CWD but PR welcome