Updated PHP version for PHP7.2+

Removed PHP5 (no longer supported)
Renamed PHP7 to PHP - consistent with other kata
Added the same helpers as other PHP Kata
Updated the code to PHP7.2+ standard
Didn't change GildedRose updateQuality method
Updated GildedRoseTest (still failing)
Added ApprovalTest (passing)
- same text file as texttests / ThirtyDays / stdout.gr (only renamed).

php/tests/ApprovalTest.php

@@ -0,0 +1,24 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests;
+
+use ApprovalTests\Approvals;
+use PHPUnit\Framework\TestCase;
+
+class ApprovalTest extends TestCase
+{
+    public function testTestFixture(): void
+    {
+        $argv[0] = 'texttest_fixture.php';
+        $argv[1] = 31;
+
+        ob_start();
+        require_once __DIR__ . '/../fixtures/texttest_fixture.php';
+        $output = ob_get_contents();
+        ob_end_clean();
+
+        Approvals::verifyString($output);
+    }
+}