FIX: issue #431 (#432)

* Fix issue #431

* docblock

* SIGTERM is used only if no value of $sig is specified

* dereuromark's suggestion

Co-authored-by: Mark Scherer <dereuromark@users.noreply.github.com>

* default $sig code = 0

* ?int => int

* update docblock signature

---------

Co-authored-by: Mark Scherer <dereuromark@users.noreply.github.com>

Author: hiryu85

src/Model/Table/QueueProcessesTable.php

@@ -290,11 +290,16 @@ public function endProcess(string $pid): void {
 	 *
 	 * @return void
 	 */
-	public function terminateProcess(string $pid, int $sig = SIGTERM): void {
+	public function terminateProcess(string $pid, int $sig = 0): void {
 		if (!$pid) {
 			return;
 		}
 
+		// In the Windows operating system the SIGTERM constant is not defined
+        if (!$sig && defined('SIGTERM')) {
+            $sig = \SIGTERM;
+        }
+		
 		$killed = false;
 		if (function_exists('posix_kill')) {
 			$killed = posix_kill((int)$pid, $sig);