quickstart.yml talks about cross.yml but that doesn't exist

[svenstaro]

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Motivation

quickstart.yml says "# For multi-OS testing see the cross.yml workflow." and I'd really like to see a complex example with a multi-os workflow (meaning a matrix-ized runs-on that runs on ubuntu-latest, macos-latest, windows-latest as well as some cross-compiled testing mixed in) but I can't find anything like that. There is cross_compile.yml but that's not quite the same.

Workflow example

Something like this: https://github.com/actions-rs/cargo/issues/72#issuecomment-622669971

[svenstaro]

Perhaps also add this as a recipe in the meta repo.