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/GildedRoseTest.php

@@ -0,0 +1,20 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests;
+
+use GildedRose\GildedRose;
+use GildedRose\Item;
+use PHPUnit\Framework\TestCase;
+
+class GildedRoseTest extends TestCase
+{
+    public function testFoo(): void
+    {
+        $items = [new Item('foo', 0, 0)];
+        $gildedRose = new GildedRose($items);
+        $gildedRose->updateQuality();
+        $this->assertSame('fixme', $items[0]->name);
+    }
+}