Mention we need to install piccolo_theme before contributing to repo

[joswhite]

When I tried to run run-docs.sh, after completing the steps in CONTRIBUTING.md I got this error:

no theme named 'piccolo_theme' found (missing theme.toml?)

Running pip install piccolo_theme fixed the issue. Perhaps we should add this to doc-requirements.txt?

[dantownsend]

It might only work from the top level - so ./scripts/run-docs.sh. That way it can find the piccolo_theme folder.

[dantownsend]

I tried this on a fresh install on Windows, and I get the same error you see. What OS are you on?

[joswhite]

I'm on Windows as well (using Git Bash)

[joswhite]

I did run it from the top level, ./scripts/run-docs.sh