Enable exporting variables across jobs on Azure Pipelines

Author: ravenpride

src/GitVersionCore.Tests/BuildServers/AzurePipelinesTests.cs

@@ -44,7 +44,7 @@ public void EscapeValues()
             var versionBuilder = new AzurePipelines(environment, log);
             var vsVersion = versionBuilder.GenerateSetParameterMessage("Foo", "0.8.0-unstable568 Branch:'develop' Sha:'ee69bff1087ebc95c6b43aa2124bd58f5722e0cb'");
 
-            vsVersion[0].ShouldBe("##vso[task.setvariable variable=GitVersion.Foo;]0.8.0-unstable568 Branch:'develop' Sha:'ee69bff1087ebc95c6b43aa2124bd58f5722e0cb'");
+            vsVersion[0].ShouldBe("##vso[task.setvariable variable=GitVersion.Foo;isOutput=true]0.8.0-unstable568 Branch:'develop' Sha:'ee69bff1087ebc95c6b43aa2124bd58f5722e0cb'");
         }
 
         [Test]

src/GitVersionCore/BuildServers/AzurePipelines.cs

@@ -21,7 +21,7 @@ public override string[] GenerateSetParameterMessage(string name, string value)
         {
             return new[]
             {
-                $"##vso[task.setvariable variable=GitVersion.{name};]{value}"
+                $"##vso[task.setvariable variable=GitVersion.{name};isOutput=true]{value}"
             };
         }