[opinion] Merge bot

[VuiMuich]

I have no real experience with such matters, but @VentGrey's recent screenshot update (no offense 😆), got me thinking if we want to consider to install some sorts of merge bot for this repo. This might help both the leftwm staff and the theme maintainers to get trivial updates pushed easier.

What do you guys think? Who would like to propose a PR to install such a bot (assuming this works just like, or is actually doable as a CI-action).