Buf v0.2.0 is released - Docker image now available

[bufbuild-announce]

We have released Buf v0.2.0. There are some internal implementation changes, but the main addition is a Docker image to enable you to use `buf` as part of your Docker workflow.

The image is available at https://hub.docker.com/r/bufbuild/buf.

To use:

$ docker run --volume "$(pwd):/workspace" --workdir /workspace bufbuild/buf:0.2.0 check lint

The documentation at https://buf.build has also been updated.

Thank you for your continued interest in Buf!