Split out Dash CI only requirements into requires-ci.txt?

[anders-kiaer]

Both pip install dash[dev] and pip install dash[testing] are extra public Dash features (respectively for building Dash components, and using the shipped Dash app test utilities).

Looking at requires-dev.txt and requires-testing.txt, there appears to have leaked https://github.com/plotly/dash CI/test suite dependencies into both files (i.e. dependencies not used by the features in dash[dev] and dash[testing]). Latest one introduced is flaky.

Split out Dash CI only dependencies to a new file?

[alexcjohnson]

Thanks @anders-kiaer - I was just thinking about exactly this last night and you're exactly right. I think internally we haven't been very clear about what these two extras mean but you're correct as to their original intent.