Also install 2.2

azure-pipelines.rx.yml

@@ -112,6 +112,10 @@ jobs:
     BuildPlatform: Any CPU
   
   steps:
+  - task: DotNetCoreInstaller@0
+    inputs:
+      version: '2.2.100'
+
   - task: DotNetCoreInstaller@0
     inputs:
       version: '3.0.100-preview-009812'