I have been contributing to nixpkgs lately and I quite enjoy
its commit message format.  I think we can adopt a similar convention, i.e.

    {project name}: {from -> to | init at version | etc}
    
    {Motivation for change. Additional information.}

To quote nixpkgs' CONTRIBUTING.md,

> For consistency, there should not be a period
> at the end of the commit message's summary line
> (the first line of the commit message).
>
> Examples:

* `bleach: 3.3.0 -> 3.3.1`
* `autocommand: init at 2.2.1`

If anyone has another idea, please feel free to chime in.
This email was written in Markdown to better distinguish
the commit messages from the email itself.  Replies should also be
in a markup language to best highlight the proposed semantics.