Update changelog to 2.1.0

hotfix: restore php8 support

add php8 support

update changelog for 2.0.2 release

add 2.0.1 release changelog

Update docs

update changelog

issue/#3: remove requirement of event name

* Update Event dispatcher, provider, and collection to do not need of event name to locate and dispatch the event.
* Update tests accordingly
* Delete EventInterface and update abstract Event

Add changelog file