Adding an example workflow for Alpine

[apoclyps]

What's Changed

Adds an example workflow and documentation for the Alpine format.

Also:

• Formats markdown and YAML using prettier
• Replaces existing test packages with Cloudsmith public example packages
• Publishes packages to https://cloudsmith.io/~cloudsmith/repos/actions/packages/

Links to https://github.com/cloudsmith-io/action/pull/1