fix: patch-nx-dep-graph for windows

[yakirgot]

on windows process.env.INIT_CWD is undefined, which makes the script fails because path.join expects strings

[ZachJW34]

I tested this on my Windows machine and the postinstall worked fine. I see this issue which you might be experiencing, so I installed npm v7.1.1 and tried running npm i and the postinstall failed with the error you are reporting. Upgrading to a newer version of npm fixed it for me. Can you post what version of npm you are using and if upgrading to a newer version fixes this issue?

[yakirgot]

My npm version at the time of opening this PR is 7.0.15. I think many developers are bound to a certain node version because of reasons, and even though this is not an issue in newer versions, we should still safe guard against old versions. 7.1.1 is a pretty new version, and I am using the LTS node version (14.x.x) at work which comes with npm 6.x.x.

On a macbook the script actually worked.

[ZachJW34]

I tested with a broken version of npm and your PR works. I agree with you, even if it is a small range of npm versions that are affected, this small patch will fix those problems. Thanks for the contribution!!