2.1.0
Add white border to banner in README to be visible in dark mode
Add alternate 'dark mode' banner to documentation
Drop support for SecureTransport (#3146)
Make Travis CI fail if docs have warnings or errors
Fix a link to "absolute URI" definition (#3128)
Generate changelog with towncrier
Fix OpenGraph metadata in docs
Drop support for Python 3.7 (#3143)
Release 2.0.0-alpha1
Importing Sphinx docs.
Remove Sphinx version pin
Remove outdated sponsorship tiers
Merge pull request from GHSA-v845-jxx5-vc9f
Allow non-OpenSSL TLS libaries with a warning