What happened (or feature request):

It turns out Xdebug doesn't work on linux with our provided instructions on v0.18.0 because Docker didn't get host.docker.internal into the linux version.

docker/for-linux#264

This isn't too hard to sort out, but it's sad.

What you expected to happen:

How to reproduce this:

Version: Please include the output of ddev version, docker version and the project's .ddev/config.yaml.

Anything else do we need to know:

Related source links or issues:

Please use a complexity rating of 1-5 (5 is high) for a feature request. (High complexity implies more PR planning)