[3.x] Run tests on PHP 8.3 and update test suite

Update PHPStan

Describe all callable arguments with types for `Promise` and `Deferred`

Fix gist link about promise in README.md

[3.x] Add template annotations

Adds template annotations turning the `PromiseInterface` into a generic.

Variables `$p1` and `$...

Add new `set_rejection_handler()` function for unhandled rejections

Report any unhandled promise rejections

[3.x] Add PHPStan to test environment with `max` level

Revert issue template changes to use organisation issue template

[3.x] Update test suite and report failed assertions

Add issue template for better orientation

Remove internal `Queue` leftovers

[3.x] feat: add support for DNF types

[3.x] Test on PHP 8.2

With PHP 8.2 coming out later this year, we should be reading for it's release to ensure all out...

chore(docs): remove leading dollar signs

Continue internal `Queue` execution also after fiber is suspended

Update test suite to avoid deprecation notices for PHP 8.1+

Support `iterable` type for `all()` + `race()` + `any()`

[RFC] Remove `done()` method

[RFC] Remove `some()`, `map()`, `reduce()` functions

[RFC] Remove unneeded `PromisorInterface`

[3.x] Add badge to show number of project installations

Require argument for `resolve()` function

Rename development branch to `3.x` and add installation instructions

Improve test suite to fix default Exception message (PHP 8.1)

Support intersection types (PHP 8.1+ / ported from v2 to v3)

PHP8.1+ complains about Exception not accepting `null` as the message
argument for an `Exception...

Add `catch()` and `finally()`, deprecate `otherwise()` and `always()`

Support PHP 8.1

Add PHP 8 support and address deprecation of ReflectionType::getClass()

Fix brackets on documentation

Use GitHub actions for continuous integration (CI)

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

Add full core team to the license

Added the full core team in order of joining the team

Initialize Deferred's state in the constructor

Update PHPUnit configuration schema for PHPUnit 9.3 and minor clean up

Add type declarations for `some()`

Run tests on PHPUnit 9 and clean up test suite

This change refactors out unnecessary and magical (= unclear,
hard-to-understand) code from Defe...

Mark `FulfilledPromise` and `RejectedPromise` as internal

Use `resolve()` and `reject()` instead.

Suggestion: when detecting promisable by method presense check its an object

Test PHP 7.4 on Travis

Clear twice to avoid leftovers in PHP 7.4 with ext-xdebug and code
coverage turned on (`vendor/b...

Simplify queue draining while retaining functionality

Add .gitattributes to exclude dev files from exports

Port memory improvements from 2.x to master