feat(live-update): add Gitea live update checking

[jaudiger]

Add new script and interface for live updating a project based on the latest release tag from a Gitea repository.

The interface is very similar to what is done with GitLab today. And its usage should be pretty straightforward:

export const project = {
  name: "gitea_docs",
  version: "0.1.0",
  repository: "https://gitea.com/gitea/docs.git",
};

export function liveUpdate(): std.Recipe<std.Directory> {
  return std.liveUpdateFromGiteaReleases({
    project,
    matchTag: /^v(?<version>.+)$/,
  });
}

[jaudiger]

@kylewlacy Once merged, I'll upstream a package that requires this new method to check for new updates.

[kylewlacy]

LGTM