Use maintained version of shoutrrr #642
Description
It seems the original shoutrrr package which is used for notifications is not seeing much activity anymore. Other consumers have apparently moved to a maintained fork https://github.com/nicholas-fedor/shoutrrr by now, which this project should do as well.
I am not sure how much API changes this brings, so someone will need to:
a. swap the dependency and fix any compiler issues that may come
b. thoroughly read the changelogs for anything that might affect users of this image