docs: add description to pyproject.toml

[jacklinke]

All Submissions:

• [x] My commit messages conform to conventional commits.
• [x] My PR title conforms to conventional commits.
• [x] I linked to any relevant issues.

Changes to / New Features:

• [x] I included the description field in pyproject.toml per the Python Packaging User Guide completing #1053

Description of changes

Adding this field will populate the description on PyPI's search page.