Jupyter_core 4.7 release candidate

The jupyter_core project has released a release candidate for 4.7.0. Changelog is up at https://jupyter-core.readthedocs.io/en/latest/changelog.html#id1. Install with pip install --pre jupyter_core==4.7.0rc0

One major enhancement is that for people running Jupyter in an environment setting (conda or virtualenv, for example), there is a new environment variable that will switch the order of the user and environment paths in the Jupyter path hierarchy, so that the environment path is more specific and overrides the user path. This means that if you are running Jupyter in virtual environments, where you may have many different virtual environments for a given user, the virtual environment config and data directories will take precedence over the user-level directories.

Please test and let us know any feedback you may have at https://github.com/jupyter/jupyter_core/issues/205. We hope to make a release next week.