Support environment URL parsing (#762)

* environment URL parsing

src/Sdk/DTWebApi/WebApi/ActionsEnvironmentReference.cs

@@ -0,0 +1,23 @@
+using System.Runtime.Serialization;
+using GitHub.DistributedTask.ObjectTemplating.Tokens;
+
+namespace GitHub.DistributedTask.WebApi
+{
+    /// <summary>
+    /// Information about an environment parsed from YML with evaluated name, URL will be evaluated on runner
+    /// </summary>
+    [DataContract]
+    public class ActionsEnvironmentReference
+    {
+        public ActionsEnvironmentReference(string name)
+        {
+            Name = name;
+        }
+
+        [DataMember(EmitDefaultValue = false)]
+        public string Name { get; set; }
+
+        [DataMember(EmitDefaultValue = false)]
+        public TemplateToken Url { get; set; }
+    }
+}