Publish arm64 Docker containers to https://hub.docker.com/r/stoplight/spectral

[akrabat]

User story.
As a specification writer, I want to validate my spec using a native Docker image on an Apple Silicon Mac so that I can run Spectral more efficiently with no warnings.

Is your feature request related to a problem?
Seeing a warning every time I run Spectral isn't a great experience.

Describe the solution you'd like
Publish arm64 images to https://hub.docker.com/r/stoplight/spectral

Additional context
When I run stoplight/spectral:latest on my Apple Silicon Mac, I see:

WARNING: The requested image's platform (linux/amd64) does not match the detected host platform (linux/arm64/v8) and no specific platform was requested

Reading #2189, I think that arm64 is now supported by Spectral, so this is a request to publish the linux/arm64 version as a native Docker image as https://hub.docker.com/r/stoplight/spectral/tags shows that only linux/amd64 are published at the moment..