fixing issues in each pipeline

.pipelines/ci/templates/build-powertoys-ci.yml

@@ -10,11 +10,11 @@ jobs:
     BuildConfiguration: ${{ parameters.configuration }}
     BuildPlatform: ${{ parameters.platform }}
   pool:
+    demands: ImageOverride -equals WinDevVS17-latest
     ${{ if eq(variables['System.CollectionUri'], 'https://dev.azure.com/ms/') }}:
       name: WinDevPoolOSS-L
     ${{ if ne(variables['System.CollectionUri'], 'https://dev.azure.com/ms/') }}:
       name: WinDevPool-L
-  demands: ImageOverride -equals WinDevVS17-latest
   timeoutInMinutes: 120
   strategy:
     maxParallel: 10

.pipelines/release.yml

@@ -193,6 +193,13 @@ jobs:
 #### MAIN SIGNING AREA
 # reference https://dev.azure.com/microsoft/Dart/_git/AppDriver?path=/ESRPSigning.json&version=GBarm64-netcore&_a=contents for winappdriver
 # https://dev.azure.com/microsoft/Dart/_git/AppDriver?path=/CIPolicy.xml&version=GBarm64-netcore&_a=contents
+# Guardian tool needs 'Microsoft.NETCore.App', version '2.1.0' (x64)
+  - task: UseDotNet@2
+    displayName: 'Use .NET Core 2.1 SDK'
+    inputs:
+      packageType: sdk
+      version: '2.1.0'
+
   - task: SFP.build-tasks.custom-build-task-1.EsrpCodeSigning@1
     displayName: Sign Core PT
     inputs: