feat: support async view functions

[summersz]

closes #22

[Ge0rg3]

Thanks again @summersz, it looks like there was a typo in the PR where asyncio.iscoroutinefunction was instead asyncio.iscoroutinefunctions, but I've gone ahead and fixed that.

I've also added your contributions to the README, they were very valuable and much appreciated 😊🙏

[summersz]

Thanks @Ge0rg3 . Good spot! I ended up making these changes in codespaces to avoid logging out of my corporate gh account, so it must have come from some poor copy and pasting!