Fixed authtest for request timeout

tests/AuthTest.php

@@ -308,7 +308,7 @@ public function testCreateTokenRequestValidity() {
 
         $this->assertFalse( $ably->auth->isUsingBasicAuth(), 'Expected token auth to be used' );
         $this->assertLessThan(
-            200,
+            300,
             abs($timestamp - $ably->auth->getTokenDetails()->issued),
             'Expected token issued timestamp to be near to the time of request (allowing for clock skew)'
         );