This is a Docker image we can use to build Rust applications.
Because the official Rust docker image is broken for 32 bit platforms like linux/arm/v7. This has been reported, but until it's fixed this image works.
If you're wondering why this image is a little larger than it needs to be,
I install a couple of other useful things that I need for my build
processes; specifically cargo-build-dependencies and cargo-audit, along
with the OS dependencies needed to build and install them and Rust itself.