Changed .Net Core Version lookup mode to multilevel

Author: azchohfi

azure-pipelines.yml

@@ -29,12 +29,14 @@ steps:
   inputs:
     packageType: 'sdk'
     version: '2.1.202' # This SDK contains .Net Core 2.0.9, which we still need to run some of our .Net Core Tests
+    performMultiLevelLookup: true
   displayName: Use .NET Core sdk 2
 
 - task: UseDotNet@2
   inputs:
     packageType: 'sdk'
     version: '3.1.200'
+    performMultiLevelLookup: true
   displayName: Use .NET Core sdk 3
 
 - task: DotNetCoreCLI@2