feat: add docker publish method

[jwillker]

As I mentioned in this issue: #55, the project could have an official docker image.

This implementation will generate a docker image on the Github container registry for amd64 and arm64 architecture for each git tag and the latest version, using Goreleaser. https://goreleaser.com/customization/docker/, https://goreleaser.com/customization/docker_manifest/

The image labels follow the annotation recommendations of https://github.com/opencontainers/image-spec/blob/main/annotations.md.

The action.yaml was changed to work with the image instead of building from Dockerfile.

Some open points:

• Makes sense to generate an image on DockerHub too? Like: https://hub.docker.com/r/google/osv-scanner
• The build step was removed from Dockerfile as the Goreleaser recommends: https://goreleaser.com/errors/docker-build/#do, but this will be more difficult for users to build the image from the source. The alternative is to have two Dockerfiles.
• For ghcr login we can use the GITHUB_TOKEN, but it can be used with a PAT. (Doc)

[another-rex]

Makes sense to generate an image on DockerHub too? Like: https://hub.docker.com/r/google/osv-scanner

For now I think just having github registry is fine.

The build step was removed from Dockerfile as the Goreleaser recommends: https://goreleaser.com/errors/docker-build/#do, but this will be more difficult for users to build the image from the source. The alternative is to have two Dockerfiles.

Agree with having two Dockerfiles, and would prefer for the goreleaser Dockerfile to be named something different.
I think it's more intuitive for the default Dockerfile to be build-able immediately upon cloning the repository.

For ghcr login we can use the GITHUB_TOKEN, but it can be used with a PAT. (Doc)

Happy to stick with GITHUB_TOKEN.

[another-rex]

/gcbrun