Update zbus and fix coding style

[jbeyerstedt]

Start of our own fork of the library. There's already a version 4 of zbus, but that one has some breaking changes according to their release notes. And our other dependencies use version 3, so upgrading would lead to two zbus versions.

Other questions: Should we merge to main or another branch?

[Bendodroid]

I have another question: Why are we making another repo for this? If we are interested in using this library going forward, why not integrate it into our monorepo?

If we are considering maintaing this publicly with the intention of others using it, I'd be curious to see how to handle crates.io because this language thought that 20 years after Java did the reverse-DNS style classpath imports it would be a great idea to make a centralized pile of globally unique crate names that cannot be reused afaik.

[jbeyerstedt]

Good question. I think my reasoning was because you started specifying a git repo instead of the local file.

As far as I understood the Apache license, it allows for private modifications. And as the upstream repo is somewhat unresponsive we can also do a private fork in our mono-repo. But on the other hand, then we have some "foreign" license stuff in our mono-repo, which might not be as easy to automatically compile to a big license statement.

[Bendodroid]

Well, the easy way afaik is to include a statement in the README saying everything under crates/systemd-client is licensed under Apache 2.0 from Li Yu and all our modifications to it are (c) consider it. Then we could also reformat the code to our guidelines, manage dependencies centrally etc.