Automatically release fleeting-plugin-aws to gitlab-runner-aws package repo

We need to automatically release changes to the fleeting-plugin-aws repository to the new gitlab-runner-aws package repo.

Based on the discussion in #2, specifically https://gitlab.com/gitlab-org/fleeting/fleeting-plugin-aws/-/issues/2#note_1237845960, the plan is to (initially):

When a plugin is released (on a separate cadence from GitLab), it is built and published to the generic package repository for that plugin. So the fleeting-plugin-aws binaries would be available at https://gitlab.com/gitlab-> org/fleeting/fleeting-plugin-aws/-/releases/v0.1.0/downloads/binaries/fleeting-plugin-aws-darwin-amd64 (for each version, for each architecture).

The manual installation instructions would tell users to "download the latest release from https://gitlab.com/gitlab-org/fleeting/fleeting-plugin-aws/-/releases".

Q: Can we provide a stable URL which points to the latest release? Like this: https://github.com/josephburnett/jd/releases/latest