Fix binder install

[goanpeca]

The docs point to using

https://jupyterlab.readthedocs.io/en/stable/extension/extension_tutorial.html#build-and-install-the-extension-for-development

pip install -e . and jupyter labextension develop --overwrite .

But the second command is missing in the binder postBuild

[fcollonval]

As stated in the mentioned link, the develop command allows to create a symbolic link from JupyterLab to our source directory. By default with pip install -e, the files will be copied not symlinked. So for binder this is ok not to run the develop command.

[goanpeca]

I made a PR the last days because this extension (https://github.com/deshaw/jupyterlab-execute-time) was not working on binder (nor locally for dev mode) if I did pip install -e .

:-|

Do I need to install jupyter-packaging for pip install -e . to do the right thing ?

https://github.com/jupyterlab/extension-cookiecutter-ts/blob/3.0/%7B%7Bcookiecutter.python_name%7D%7D/setup.py#L72

Is that is the case then we would need to add that to environment.yml since it is not longer on install-requires ?

[blink1073]

Yes, this makes sense because pip does not handle data_files in develop mode.

[fcollonval]

Ho yep sorry @goanpeca I forgot that now jupyter-packaging is optional. So thanks @blink1073 for merging this one.