Update ci-build.yaml for Azure Pipelines

ci-build.yaml

@@ -3,6 +3,7 @@
 # Add steps that run tests, create a NuGet package, deploy, and more:
 # https://docs.microsoft.com/azure/devops/pipelines/languages/dotnet-core
 
+
 trigger:
   branches:
     include:
@@ -20,7 +21,11 @@ pool:
   vmImage: 'ubuntu-latest'
 
 steps:
-
+- task: UseDotNet@2
+  displayName: Use dotnet sdk
+  inputs:
+    packageType: 'sdk'
+    version: '2.2.401'
 - task: DotNetCoreCLI@2
   displayName: Run Unit Tests
   inputs: