Comparable enum (#20)

* feat: comparable enum

* test: comparable enum

* ci: php-cs-fixer in repository scope

* chore: add `Comparable` usage in README

* ci: globally use `php-cs-fixer`

* improve Comparable logic

* test more PHP versions in CI

* update ci job name

* remove class name quoting in exceptions to match PHP behavior

* migrate pest config

* add comment to test

---------

Co-authored-by: Samuel Štancl <samuel@archte.ch>
Co-authored-by: Samuel Štancl <samuel.stancl@gmail.com>

README.md

@@ -8,6 +8,7 @@ A collection of enum helpers for PHP.
 - [`Options`](#options)
 - [`From`](#from)
 - [`Metadata`](#metadata)
+- [`Comparable`](#comparable)
 
 You can read more about the idea on [Twitter](https://twitter.com/archtechx/status/1495158228757270528). I originally wanted to include the `InvokableCases` helper in [`archtechx/helpers`](https://github.com/archtechx/helpers), but it makes more sense to make it a separate dependency and use it *inside* the other package.
 
@@ -366,6 +367,65 @@ enum TaskStatus: int
 
 And if you're using the same meta property in multiple enums, you can create a dedicated trait that includes this `@method` annotation.
 
+### Comparable
+
+This helper lets you compare enums by `is()`, `isNot()`, `in()` and `notIn()` operators.
+
+#### Apply the trait on your enum
+```php
+use ArchTech\Enums\Comparable;
+
+enum TaskStatus: int
+{
+    use Comparable;
+
+    case INCOMPLETE = 0;
+    case COMPLETED = 1;
+    case CANCELED = 2;
+}
+
+enum Role
+{
+    use Comparable;
+
+    case ADMINISTRATOR;
+    case SUBSCRIBER;
+    case GUEST;
+}
+```
+
+#### Use the `is()` method
+```php
+TaskStatus::INCOMPLETE->is(TaskStatus::INCOMPLETE); // true
+TaskStatus::INCOMPLETE->is(TaskStatus::COMPLETED); // false
+Role::ADMINISTRATOR->is(Role::ADMINISTRATOR); // true
+Role::ADMINISTRATOR->is(Role::NOBODY); // false
+```
+
+#### Use the `isNot()` method
+```php
+TaskStatus::INCOMPLETE->isNot(TaskStatus::INCOMPLETE); // false
+TaskStatus::INCOMPLETE->isNot(TaskStatus::COMPLETED); // true
+Role::ADMINISTRATOR->isNot(Role::ADMINISTRATOR); // false
+Role::ADMINISTRATOR->isNot(Role::NOBODY); // true
+```
+
+#### Use the `in()` method
+```php
+TaskStatus::INCOMPLETE->in([TaskStatus::INCOMPLETE, TaskStatus::COMPLETED]); // true
+TaskStatus::INCOMPLETE->in([TaskStatus::COMPLETED, TaskStatus::CANCELED]); // false
+Role::ADMINISTRATOR->in([Role::ADMINISTRATOR, Role::GUEST]); // true
+Role::ADMINISTRATOR->in([Role::SUBSCRIBER, Role::GUEST]); // false
+```
+
+#### Use the `notIn()` method
+```php
+TaskStatus::INCOMPLETE->notIn([TaskStatus::INCOMPLETE, TaskStatus::COMPLETED]); // false
+TaskStatus::INCOMPLETE->notIn([TaskStatus::COMPLETED, TaskStatus::CANCELED]); // true
+Role::ADMINISTRATOR->notIn([Role::ADMINISTRATOR, Role::GUEST]); // false
+Role::ADMINISTRATOR->notIn([Role::SUBSCRIBER, Role::GUEST]); // true
+```
+
 ## PHPStan
 
 To assist PHPStan when using invokable cases, you can include the PHPStan extensions into your own `phpstan.neon` file: