Define release approach and project prioritisations

[xd009642]

So as briefly mentioned in https://groups.google.com/a/tensorflow.org/g/rust/c/Ctov9Caw1YU would be nice to come up with some general release schedule or a prioritisation for features for next releases. I'm personally a fan of releasing early and often as it gives people a chance to try out new features sooner. Like at any point a significant new feature is added i.e. the recent ndarray feature and is usable I'd cut a release on one of my own projects.

Also having CI automate the releases when a tag is pushed is an approach I've found keeps it low effort for maintainers 😄 I have some CI scripts for travis or github actions which I could potentially contribute though there's an abundance of recipes online as well for Rust.