update typing_extensions (#170)

Why
===
* The old version pin was incompatible with newer libraries
* #125

What changed
===
* Updated pyprojecet.toml to pin typing_extensions to be any 4.x.x release
* Ran poetry lock

Test plan
===
* CI passes
* Make a project that imports the replit-py release and
typing-extensions and see it doesn't fail

Author: ryantm