Add badge to show number of project installations

Optimize Promise v3 API compatibility to avoid hitting autoloader

Improve forward compatibility with upcoming Promise v3 API

Add new `sleep()` function and deprecate `resolve()` and `reject()` functions

Improve `TimeoutException` legacy API by using explicit type casts

Improve API documentation and add parameter types and return types

Support PHP 8.1

Simplify usage by supporting new default loop

Use GitHub actions for continuous integration (CI)

Bye bye Travis CI, you've served us well.

Update PHPUnit configuration schema for PHPUnit 9.3

Add full core team to the license

Added the full core team in order of joining the team

Run tests on PHPUnit 9 and clean up test suite

Forward compatibility with react/promise 3