Generate examples json files at test time

[dbirman]

Is your feature request related to a problem? Please describe. Right now maintainers have to run the examples generator manually to get JSON example files to pass test_examples.py, adding an (unnecessary) extra step

Describe the solution you'd like Probably add a workflow that runs the examples generator on new commits and pushes the updates to the repo, before running tests. Or alternatively re-generate the examples at test time to confirm they pass