New ARM64 image on docker hub

[dprinz]

I had problems running the image spencermksmith/auto-m4b on my mac. Since its already a year old and doesn't include the latest changes from this repo, I decided to build a new image and upload it.
You can use dprinz/auto-m4b. it run's fine on macs. Not tested on Rasberry Pi yet but will do that soon.
Feel free to use the image.