Publish pbandk as a buf remote plugin

[garyp]

• Adopt the Dockerfile mentioned in the below discussion into the main pbandk git repo.
• Publish new versions of the docker image to the buf docker registry from pbandk's GitHub Actions release workflow

Discussed in #223

^{Originally posted by julienfouilhe June 27, 2022}
Hi,

I created a buf plugin for pbandk. Dockerfile is available here.

This allows buf users to use pbandk as a remote plugin without having to install it locally.

I'm not very familiar with java so I couldn't make a smaller image work. Also pbandk problem running as root meant I had to add a custom user.

Would you be interested in taking the ownership of that repository and publishing the plugin to the buf registry yourself?

[garyp]

Looks like the process around Buf plugins has changed. The Buf team now maintains all plugins themselves. To get a pbandk plugin added to the Buf Registry, we need to first create an issue using the template at https://github.com/bufbuild/plugins/issues/new/choose. Then we can create a PR following the instructions at https://github.com/bufbuild/plugins/blob/main/CONTRIBUTING.md with the Dockerfile for the pbandk plugin and other required metadata.