In accordance with [this advisory](https://github.blog/changelog/2020-10-01-github-actions-deprecating-set-env-and-add-path-commands/) it's recommended we moved to a different scheme of setting env vars and updating PATH.
install-rust
A small github action to install rustup and a Rust toolchain. This is
generally expressed inline, but it was repeated enough in this repository it
seemed worthwhile to extract.
Some gotchas:
- Can't
--self-updateon Windows due to permission errors (a bug in Github Actions) rustupisn't installed on macOS (a bug in Github Actions)
When the above are fixed we should delete this action and just use this inline:
- run: rustup update $toolchain && rustup default $toolchain
shell: bash