Merge pull request #159 from pcubillos/docs

sphinx requirement back to docs_requirements.txt

set sphinx version in ../.readthedocs.yml for docs

Set requirement for docs sphinx<8.20 until that get's sorted out

Fixed typo

Added sphynx req to docs_requirements.txt

Merge pull request #158 from pcubillos/update

Updated version to 3.2.1

Updated copyright year

Tweaked mcmc tests

Fixed python3.8+ 'bug' where collections is no longer accessible

Cosmetics

Added adjustment for horizontal and vertical alignment in rainbow_text()

Merge pull request #156 from pcubillos/numpy2

Updated version to 3.2.0.