Add CHANGELOG 2.1.0

[philippjfr]

I plan to release in the morning.

Version 2.1.0

Date: 2024-01-22

This minor release focuses on improving reactive expressions and support for asynchronous (and synchronous) generators. Many thanks to @maximelt, @Hoxbro and @philippjfr for their continued maintenance and development efforts.

Enhancements

• Improvements for synchronous and asychronous generators (#908)
• Additions to the .rx namespace including and_, bool, map, not_, or_, updating (#906)
• Add support for asynchronous watcher to rx (#917)
• Make it possible to resolve rx expressions recursively with .rx.resolve (#918)
• Add support for async and generator functions in .rx.pipe (#924)

Bug fixes

• Ensure that .param.update context manager restore refs (#915)
• Avoid overeager root invalidation on rx leading to unnecessary evaluation (#919)

Deprecations

• Passing positional arguments to Parameter now raises a ParamDeprecationWarning (#921)