Show dependency status of main branch in README

[dodomorandi]

It is a bit misleading to show the status of the last published version, because some issues could have been already resolved and this is not clear at a first glance.

Feel free to close this PR if the current behavior is intended.

[paolobarbolini]

Honestly I'm not sure how this should work. On one hand, I think badges are more useful when looking at the README within GitHub, so it would make sense to show the state of the repository. On the other hand, I also wish they were more useful on crates.io, but that can't happen if they show the repo status or the status of another release.

What do you think about this?

[dodomorandi]

🤔 I think that you are absolutely right, and that this issue probably never received enough attention.

Let me try a different approach, give me just a few minutes.

[dodomorandi]

Ok, my idea is simple but it requires some changes to badges from deps.rs.

If we could customize badge labels, it would be possible to use two different badges, one for the last release and one for the main branch. However, without the ability of customizing labels it would be impossible to understand the relationship between badges, repo and releases.

I am going to close this PR for now (it is simple enough to open another one if things get better), because I would rather to inform crates.io users that the last release has an old dependency even if this can be a bit misleading on GH.