Add NuGet feed auth to build

build.yml

@@ -9,6 +9,11 @@ pool:
 
 steps:
 
+- task: NuGetAuthenticate@0
+  displayName: Authenticate NuGet feeds
+  inputs:
+    forceReinstallCredentialProvider: true
+
 - task: DotNetCoreCLI@2
   displayName: Build and Package
   inputs: