@timcera There was a change in some prior version of environment.yml, which is called by setup.py. When the jupyterlab=3.0.* is used, pip install . fails with a cryptic warning of:

error in HSPsquared setup command: 'extras_require' must be a dictionary whose values are strings or lists of strings containing valid project/version requirement specifiers.`

It appears that this - jupyterlab =3.0.* was not good syntax(?), so:

• I tested first by reverting to a previous working version, jupyterlab >=3.0.14. installed just fine.
• I tested - jupyterlab ==3.0.* (note extra '=' sign), which is the format used by other modules, and it also installed just fine.

Presuming that the extra '=' was what was intended, I kept the 3.0.* version, though wondered if the >= syntax might be preferable as it would then be compatible with 3.1+? I dunno. But if someone thinks we should use a >= syntax, I can go back and do a new PR with that fix.

-  - jupyterlab >=3.0.14  # also installs classic Jupyter notbook
+  - jupyterlab =3.0.*  # also installs classic Jupyter notbook

Also in this PR - some cleaned up code to add stubs for special actions.