3.2.0

• Dark mode is now handled automatically on iOS 15–16 as well; calling refreshNeumorphicShadows() by hand is no longer needed on any version.
• Fixed a leak where re-styling a view (for example a reused cell) stacked a new light/dark observer on top of the old one.
• Added the MIT license.
• Added a CI workflow that builds and tests on every push.
• Rewrote the README in plainer language.