docs: fix typo in setup guide

[meichuanyi]

Fixes a small spelling typo in setup.md: enviroment → environment.

This is a documentation-only change.

[CLAassistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.
_{You have signed the CLA already but the status is still pending? Let us recheck it.}