Update PyProject Toml - License

[haohaocreates]

Hey! HaoHao from comfy.org again 😊.

As a heads up, the license field is optional but in the case that it is filled out, the license file should be referenced as follows

• license = { file = "LICENSE" } ✅
• license = "LICENSE" ❌

This was brought up in our discord and so we're creating a small PR to update that optional field. For more info check out toml file standards or our docs page!