Bring TLJH up to date

[GeorgianaElena]

Background

TLJH is a bit behind adopting new technology and needs some care and love to become more up to date. There might also be functionality missing or not working because of this. But this needs more investigating before knowing for sure.

Expected timeline

It shouldn't take more than a month or two to upgrade TLJH, but it would probably also need some maintenance afterwards to make sure it works for all use-cases and we didn't miss anything. So, I propose we keep this goal open for about 3 months and actively maintain TLJH during this period. # How will we know when this goal is complete? - [x] Fix pkg version conflict in TLJH `jupyterhub-traefik-proxy`has `aiohttp` pinned to an older version so that it works with the consul python client. However, this pin clashed with `chardet` latest version and impacted tljh-config` functionality and has been fixed by pinning the `chardet` version. Now, the pin in `traefik-proxy` made the unit tests to stop functioning. The pin should be removed if possible, or pin any necessary pkg in unit test requiremets to make it work again.` - [x] Unpin `aiohttp` in `traefik-proxy` - [x] Cut a new `jupyterhub-traefik-proxy` release - [x] Default to Ubuntu 20.04 and Python 3.8 - [x] Default to JupyterLab3 (this should also lower the minimum memory required to install and run TLJH) - [x] Make the tests use GitHub actions instead of CircleCI - [x] Investigate deploying the [JupyterHub Configurator](https://github.com/yuvipanda/jupyterhub-configurator), potentially turning into a visual of `tljh-config` cmd tool. # Related issues and links - https://github.com/jupyterhub/the-littlest-jupyterhub/issues/642 - https://github.com/jupyterhub/traefik-proxy/pull/115 - https://github.com/jupyterhub/the-littlest-jupyterhub/issues/665 - https://github.com/jupyterhub/the-littlest-jupyterhub/pull/658 - https://github.com/jupyterhub/the-littlest-jupyterhub/issues/659 - https://github.com/jupyterhub/the-littlest-jupyterhub/issues/618 - https://github.com/jupyterhub/the-littlest-jupyterhub/pull/676

I'm closing this as there have been more than 3 months (the intended period for this issue to be open) and most of the items have been addressed.

The TLJH maintenance effort is now being tracked by https://github.com/jupyterhub/the-littlest-jupyterhub/issues/711 (thanks @consideRatio, @yuvipanda and @manics :tada:)