Request to update the image and strip some unnecessary parts

[DJFliX]

Hi! Thanks for this image! It helped me get acquainted with rp2040 development on different platforms without having to set the entire toolchain on every different OS that I work on (Linux, Mac, Windows).

While using this image to contribute to other projects I noticed that this image would happily compile my project, but the workflows of the projects failed. It seems that this image is a bit outdated.

Because of that I have forked the repo and published an updated version (which allows me to continue tinkering).

Would you be interested in a PR for the changes that I made? I've stripped some stuff as well to reduce the overall image size by about 30%. I'm sure we can squeeze out a bit more by removing even more architectures, but I thought it was a good start :).