Proposal: Wasmtime 1.0

I wanted to raise awareness in this repository about the [proposal for Wasmtime to become 1.0](https://github.com/bytecodealliance/rfcs/pull/14#issuecomment-915589031). If others are watching just this repository and are interested to learn what 1.0 would mean for Wasmtime and this embedding, feel free to read over the RFC and leave comments!