marionette_driver 3.1.0 has been released. This release contains changes
that allow marionette_driver to work in Python 3, although further
changes will be required for full Python 3 support.
In line with the previously announced deprecation plan, there is no
planned release of marionette_harness. Future marionette_driver releases
will be confined to compatibility fixes.
The full list of changes in this release are detailed in
https://bugzilla.mozilla.org/show_bug.cgi?id=1654537