Remove SIGKILL handling from reactphp (#136)

Co-authored-by: Alexander Schranz <[email protected]>

Author: ash-m

src/ServerFactory.php

@@ -36,9 +36,6 @@ public function createServer(RequestHandlerInterface $requestHandler): LoopInter
         $loop->addSignal(SIGTERM, function (int $signal) {
             exit(128 + $signal);
         });
-        $loop->addSignal(SIGKILL, function (int $signal) {
-            exit(128 + $signal);
-        });
         $server = new HttpServer($loop, function (ServerRequestInterface $request) use ($requestHandler) {
             return $requestHandler->handle($request);
         });