actions: added PHP script to update versions

.github/workflows/update-php-versions.php

@@ -0,0 +1,51 @@
+<?php
+
+/*
+ *
+ *  ____            _        _   __  __ _                  __  __ ____
+ * |  _ \ ___   ___| | _____| |_|  \/  (_)_ __   ___      |  \/  |  _ \
+ * | |_) / _ \ / __| |/ / _ \ __| |\/| | | '_ \ / _ \_____| |\/| | |_) |
+ * |  __/ (_) | (__|   <  __/ |_| |  | | | | | |  __/_____| |  | |  __/
+ * |_|   \___/ \___|_|\_\___|\__|_|  |_|_|_| |_|\___|     |_|  |_|_|
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * @author PocketMine Team
+ * @link http://www.pocketmine.net/
+ *
+ *
+*/
+
+declare(strict_types=1);
+
+const VERSIONS = [
+	"7.3",
+	"7.4",
+	"8.0"
+];
+
+$workflowFile = file_get_contents(__DIR__ . '/main.yml');
+$newWorkflowFile = $workflowFile;
+foreach(VERSIONS as $v){
+	$releaseInfo = file_get_contents("https://secure.php.net/releases?json&version=$v");
+	if($releaseInfo === false){
+		throw new \RuntimeException("Failed to contact php.net API");
+	}
+	$data = json_decode($releaseInfo, true);
+	if(!is_array($data) || !isset($data["version"]) || !is_string($data["version"]) || preg_match('/^\d+\.\d+\.\d+(-[A-Za-z\d]+)?$/', $data["version"]) === 0){
+		throw new \RuntimeException("Invalid data returned by API");
+	}
+	$updated = preg_replace("/$v\.\d+/", $data["version"], $newWorkflowFile);
+	if($updated !== $newWorkflowFile){
+		echo "Updated $v revision to " . $data["version"] . "\n";
+	}
+	$newWorkflowFile = $updated;
+}
+
+if($workflowFile !== $newWorkflowFile){
+	echo "Writing modified workflow file\n";
+	file_put_contents(__DIR__ . '/main.yml', $newWorkflowFile);
+}