app center；增加發送ping的秒

Assets/AppCenter/Plugins/AppCenterSDK/Distribute/Shared/UpdateTrack.cs

@@ -0,0 +1,18 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT license.
+
+namespace Microsoft.AppCenter.Unity.Distribute
+{
+    public enum UpdateTrack
+    {
+        /// <summary>
+        /// Releases from the public group that don't require authentication.
+        /// </summary>
+        Public = 1,
+
+        /// <summary>
+        /// Releases from private groups that require authentication, also contain public releases.
+        /// </summary>
+        Private = 2
+    }
+}