Merge pull request #888 from goldsam/feat/859-output-true

write variables as both output and non-output in VSTS.

Author: AArnott

src/NerdBank.GitVersioning/CloudBuildServices/VisualStudioTeamServices.cs

@@ -39,7 +39,11 @@ public IReadOnlyDictionary<string, string> SetCloudBuildNumber(string buildNumbe
     public IReadOnlyDictionary<string, string> SetCloudBuildVariable(string name, string value, TextWriter stdout, TextWriter stderr)
     {
         Utilities.FileOperationWithRetry(() =>
-            (stdout ?? Console.Out).WriteLine($"##vso[task.setvariable variable={name};]{value}"));
+        {
+            TextWriter output = stdout ?? Console.Out;
+            output.WriteLine($"##vso[task.setvariable variable={name};]{value}");
+            output.WriteLine($"##vso[task.setvariable variable={name};isOutput=true;]{value}");
+        });
         return GetDictionaryFor(name, value);
     }