feat: add toBeUlid assertion and isUlid validation method (#1726)

tests/Features/Expect/toBeUlid.php

@@ -0,0 +1,26 @@
+<?php
+
+use Pest\Exceptions\InvalidExpectationValue;
+use PHPUnit\Framework\ExpectationFailedException;
+
+test('failures with wrong type', function () {
+    expect([])->toBeUlid();
+})->throws(InvalidExpectationValue::class, 'Invalid expectation value type. Expected [string].');
+
+test('pass', function () {
+    expect('01ARZ3NDEKTSV4RRFFQ69G5FAV')->toBeUlid();
+    expect('01BX5ZZKBKACTAV9WEVGEMMVRE')->toBeUlid();
+    expect('7ZZZZZZZZZ0000000000000000')->toBeUlid();
+});
+
+test('failures', function () {
+    expect('foo')->toBeUlid();
+})->throws(ExpectationFailedException::class);
+
+test('failures with message', function () {
+    expect('bar')->toBeUlid('oh no!');
+})->throws(ExpectationFailedException::class, 'oh no!');
+
+test('not failures', function () {
+    expect('foo')->not->toBeUlid();
+});