Fix CI Build Errors on Build Windows Samples job (#1173)

* Update azure-pipelines.yml

* Clean + Build

* Revert "Clean + Build"

This reverts commit e93ca82.

* Add `dotnet clean`

* Update azure-pipelines.yml

* Update azure-pipelines.yml

* Update azure-pipelines.yml

* Add link

azure-pipelines.yml

@@ -61,6 +61,15 @@ jobs:
     pool:
       vmImage: windows-2019
     steps:
+      - task: CmdLine@2
+        displayName: 'Clear Local NuGet Cache' #https://github.com/actions/virtual-environments/issues/1090#issuecomment-748452120
+        inputs:
+          script: 'nuget locals all -clear'
+      - task: MSBuild@1
+        displayName: 'Clean Solution'
+        inputs:
+          solution: $(PathToSln)
+          msbuildArguments:  '/t:Clean'
       - task: MSBuild@1
         displayName: Build Solution
         inputs:
@@ -88,6 +97,15 @@ jobs:
         inputs:
           version: $(NETCORE_TEST_VERSION_2_1)
           includePreviewVersions: false
+      - task: CmdLine@2
+        displayName: 'Clear Local NuGet Cache' #https://github.com/actions/virtual-environments/issues/1090#issuecomment-748452120
+        inputs:
+          script: 'nuget locals all -clear'
+      - task: MSBuild@1
+        displayName: 'Clean Solution'
+        inputs:
+          solution: $(PathToSln)
+          msbuildArguments:  '/t:Clean'
       # if this is a tagged build, then update the version number
       - powershell: |
           $buildSourceBranch = "$(Build.SourceBranch)"