Link to docker image seems broken

[Kroh-N]

Dear Christoph,

In your readme.md file there seems to be a small error in the link pointing to the docker image:

https://registry.hub.docker.com/u/chrishah/mitobim/ should be replaced by
https://registry.hub.docker.com/r/chrishah/mitobim

Best wishes from the Vienna Museum,
Nicolas & Andreas