Container does not run on armv8

[echo-bravo-yahoo]

Error in docker-compose at up/build/image fetch time:

 subsonic Pulled 
 Container music-subsonic-1  Creating
 subsonic The requested image's platform (linux/amd64) does not match the detected host platform (linux/arm64/v8) and no specific platform was requested 
 Container music-subsonic-1  Created
 Container music-subsonic-1  Starting
 Container music-subsonic-1  Started

Error in container at runtime:
exec /opt/subsonic/entrypoint.sh: exec format error

It looks like the container likely needs to be built as a multi-arch container with an armv8 build for this to work.

[echo-bravo-yahoo]

Since this image is Ubuntu-based and Ubuntu publishes armv8 images, it looks like this should be really easy to fix!

I pulled the repository and did a local build with sudo docker buildx build --platform linux/arm64/v8 --tag subsonic-custom . and it built & is working great.

I'd open a PR, but the build script / infra doesn't appear to be committed.