Update docker image

[nlehuby]

There are several new releases of libosmium and osmium-tools. Can you please update the dockerhub image ?

[milovanderlinden]

I am trying to make a new Dockerfile that builds. Once it is finished, I will create a pull request.

[FDenker]

If anyone finds this (like I did a few days ago) it is probably easiest to just create a docker image using a Dockerfile with the following content:

FROM ubuntu:20.04

RUN apt-get update
RUN apt-get update && apt-get install -y \
    osmium-tool

This is really super basic but gets all the relevant dependencies without having to try to get CMAKE to work...