* Upgrade our github actions to "node16" Each github actions run has a lot of warnings about using node12 so this upgrades our repository to using node16. I'm hoping no other changes are needed and I suspect other actions we're using are on node12 and will need further updates, but this should help pin down what's remaining. * Update `actions/checkout` workflow to `v3` * Update to `actions/cache@v3` * Update to `actions/upload-artifact@v3` * Drop usage of `actions-rs/toolchain` * Update to `actions/setup-python@v4` * Update mdbook version
binary-compatible-builds
A small (ish) action which is intended to be used and will configure builds of Rust projects to be "more binary compatible". On Windows and macOS this involves setting a few env vars, and on Linux this involves spinning up a CentOS 6 container which is running in the background.
All subsequent build commands need to be wrapped in $CENTOS to optionally run
on $CENTOS on Linux to ensure builds happen inside the container.