#5 fix version in User Agent

Author: dnl-blkv

BunqSdk/Http/ApiClient.cs

@@ -39,7 +39,7 @@ public class ApiClient
         /// Values for the default headers
         /// </summary>
         private const string CACHE_CONTROL_NONE = "no-cache";
-        private const string USER_AGENT_BUNQ = "bunq-sdk-csharp/0.9.0";
+        private const string USER_AGENT_BUNQ = "bunq-sdk-csharp/0.9.1-beta";
         private const string LANGUAGE_EN_US = "en_US";
         private const string REGION_NL_NL = "nl_NL";
         private const string GEOLOCATION_ZERO = "0 0 0 0 NL";