Create dependency PRs with GitHub App

[redeboer]

Currently, automatically created PRs like ComPWA/ampform-dpd#130 are 'authored' by @redeboer. This is because it was easiest to give the proper push rights to a user account. It would be better though if the PRs are authored by a bit, just like pre-commit.ci does (see e.g. ComPWA/gluex-nstar#12).

[redeboer]

@shenvitor this also makes it possible for me to review these maintenance PRs 😅

[shenvitor]

@shenvitor this also makes it possible for me to review these maintenance PRs 😅

So... Shall I do this later?

[redeboer]

Nah not a high priority ;)