Added string header to mqtt client.

JonathanHenson · JonathanHenson · commit 21ad975c926c · 2018-11-19T21:41:04.000-08:00
diff --git a/include/aws/crt/mqtt/MqttClient.h b/include/aws/crt/mqtt/MqttClient.h
@@ -21,6 +21,7 @@
 
 #include <functional>
 #include <memory>
+#include <string>
 
 namespace Aws
 {
