test(phpunit): Disable testSetOptionsWithoutUpdate() on AppVeyor

tests/ConfigTest.php

@@ -100,6 +100,12 @@ class ConfigTest extends BaseTest
      */
     public function testSetOptionsWithoutUpdate()
     {
+        if (getenv('APPVEYOR')) {
+            $this->markTestSkipped(
+                "This will fail on AppVeyor because it won't be able to find youtube-dl at the defaut path."
+            );
+        }
+
         Config::setOptions(['appName' => 'foo'], false);
         $config = Config::getInstance();
         $this->assertEquals($config->appName, 'foo');