Add option to create separate PRs for each updated dependency

[darkdragon-001]

It is a lot easier to find out which updated dependency caused a failure or temporarily ignore a single update while auto-merging others. This is also well explained in the decision decisions of a similar tool.

So it would be great if such an option existed here as well!

[wjt]

I agree that this would be interesting to try!

One note: right now the way the bot avoids opening the same pull request more than once is that it derives the name of the branch from the contents of the repository. This design worked well when it was only updating a single module; nowadays it can be quite annoying if you try to skip updates to a single dependency, because each time you accept an update to some other module, the tree hash changes, and so the bot will re-propose other updates you skipped. (Other times this can actually be useful, e.g. if you skip it because you're waiting for a corresponding update in another component.)

In a one-PR-per-module model, I think you'd want to derive the name of the branch from (e.g.) the sha256sum of the tarball / commit ID of the source. That would ensure that the bot would never re-propose the same update.