## Description
Updates `CONTRIBUTING.md` to include some basic guidance to new
contributors
and instructions for maintainers for syncing quinn
## Breaking Changes
n/a
## Notes & open questions
Not meant to be super extensive. We could add more as we find what works
best
for this repo
## Change checklist
<!-- Remove any that are not relevant. -->
- [x] Self-review.
- [x] Documentation updates following the [style
guide](https://rust-lang.github.io/rfcs/1574-more-api-documentation-conventions.html#appendix-a-full-conventions-text),
if relevant.
- [x] This PR was created by a human that thought critically about the
proposed change and wrote an as clear and concise description as
they could.
- [x] This PR isn't slop, and is carefully crafted to do have the
intented effect.
- [x] `cargo make` passes locally.
Diva Martínez