From the official docs:
```
Note: The official Debian and Ubuntu images automatically run apt-get clean, so explicit invocation is not required.
```
Also added ` && rm -rf /var/lib/apt/lists/*` as part of the install line which probably does what was intended (no need to make a new layer).
Added apt-get update to the RUN payload, as it should be part of the same layer.
Both are documented here: https://docs.docker.com/engine/userguide/eng-image/dockerfile_best-practices/
Some links were still pointing to `/keyboards/ergodox_ez`, while the
directory is `/keyboards/erdogox` now.
Not all references have been updated, and some of the text here and
there may need updating to mention the ErgoDox Infinity too, but that's
out of the scope for this quick fix.
Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>
