Docker Hub and advertising riscv64 support

[ibennetch]

Hi, this might be related to #218 but I'm not that certain. Also, I'm not sure if it belongs here or at https://github.com/docker-library/official-images/issues/

Docker Hub seems to be confused about riscv64 support in alpine; tags 20210804 and edge are reporting invalid architecture riscv64. This breaks using bashbrew (and therefore also generate-stackbrew-library.sh with any alpine image such we do with our tests at phpMyAdmin.

$ bashbrew cat https://github.com/docker-library/official-images/raw/master/library/alpine

failed fetching repo "https://github.com/docker-library/official-images/raw/master/library/alpine"
Tags "20210804, edge" has invalid Architectures: "riscv64"

https://github.com/docker-library/official-images/blob/master/library/alpine#L5 looks like riscv64 support is present, and https://github.com/docker-library/bashbrew/blob/master/architecture/oci-platform.go#L25 looks like bashbrew should accept it as a valid architecture.

I'm a little out of my element on this; can you shed some light on what's going on here?

[jiangxiaobin96]

Is there any progress here?