Support JupyterLab 2.0.0

[consideRatio]

JupyterLab 2.0.0 is out, and this extension have conflicting dependencies with its core packages. Fixes #88.

Conflicting Dependencies:
JupyterLab                        Extension      Package
>=2.0.0 <2.1.0                    >=1.1.3 <2.0.0 @jupyterlab/application
>=2.0.0 <2.1.0                    >=1.1.3 <2.0.0 @jupyterlab/apputils
>=2.0.0 <2.1.0                    >=1.1.3 <2.0.0 @jupyterlab/notebook
>=2.0.0 <2.1.0                    >=1.4.0 <2.0.0 @jupyterlab/rendermime-interfaces
>=5.0.0 <5.1.0                    >=4.1.1 <5.0.0 @jupyterlab/services

Implementation notes

There was some manual changes needed in the code due to the following part in the JupyterLab migration guide: https://jupyterlab.readthedocs.io/en/stable/developer/extension_migration.html#using-session-and-sessioncontext-to-manage-kernel-sessions

I did my best to ensure I didn't get install / build errors, and made a guess on how to fix it. I have not tested this code in a JupyterLab UI yet.

References

• Change log for developers
• A migration guide

[mattpap]

$ python -m jupyterlab.selenium_check /home/travis/miniconda/bin/python: No module named jupyterlab.selenium_check The command "python -m jupyterlab.selenium_check" exited with 1.

If selenium_check was removed, then we will have to remove this part of the build.

[consideRatio]

It was renamed, ill update for that when im at my computer! (on mobile now)

jupyterlab/jupyterlab#4872

[consideRatio]

Trusty is 14.04 (6 year old LTS)
Xenial is 16.04 (4 year old LTS)
Bionic is 18.04 (2 year old LTS --- seems most reasonable to use)

sudo: false is a setting that is now deprecated and does nothing.

[mattpap]

We will need to eventually migrate this repo to github actions to unify with bokeh.

[consideRatio]

We didn't need selenium now when we are using the browser_check script instead of the selenium_check script, and I think geckodriver / firefox is meant for selenium.

[consideRatio]

Okay! I think I'm happy with the PR as it is given what I know and understand currently.

[mattpap]

@consideRatio, thanks for fixing this.

[codypiersall]

Thanks a bunch @consideRatio, just confirmed that it works for me!

[consideRatio]

@mattpap my attribution for this contribution was erased from the git history through the way this PR was squashed and merged =/

[philippjfr]

Very odd, never seen a squash merge do that before.

[mattpap]

@consideRatio, it's unfortunate and must be a bug in GitHub. Squash and merge is supposed to preserve the original author and at most should have added me as a co-author. I checked a few recently merged PRs and it seems it's an isolated event.

[bryevdv]

Looks like a recent (bad) intentional change at GH:

https://twitter.com/andyhayden1/status/1235593402709716992?s=20

[bryevdv]

I poked Nat Friedman on twitter and a "fix should be deployed today" :D

@consideRatio We very much appreciate your contribution, I know it's a cliche to say that the reward for good work is more work, but please let us know if we we can help you find another good PR for you to submit that will properly credit you.