http changed to https

Author: Justinas Pošiūnas

src/Common/ApiConstants.php

@@ -3,7 +3,7 @@
 namespace MailerLiteApi\Common;
 
 class ApiConstants {
-    const BASE_URL = "http://api.mailerlite.com/api/";
+    const BASE_URL = "https://api.mailerlite.com/api/";
     const VERSION = "v2";
     const SDK_USER_AGENT = "MailerLite PHP SDK";
     const SDK_VERSION = "2.0";