Bump Sphinx Theme to 1.11

[Eric-Arellano]

Summary

Major changes include:

1. Fixing IBM fonts not loading
2. Fixing jQuery missing and some JavaScript errors
3. Making the right page table of contents sticky when you scroll down the page.

Details and comments

This also fixes pyproject.toml to add the missing build-backend key. And it removes wheel from what is required, since you don't actually need that.

Finally, it fixes tox -e docs not working on macOS by setting usedevelop = False like we had to do in Terra.