[release/9.0] Install .NET 8 before running Publish Using Darc (#16265)

Author: dkurepa

eng/common/core-templates/job/publish-build-assets.yml

@@ -145,6 +145,11 @@ jobs:
           PromoteToChannelIds: ${{ parameters.PromoteToChannelIds }}
           is1ESPipeline: ${{ parameters.is1ESPipeline }}
 
+      # Darc is targeting 8.0, so make sure it's installed
+      - task: UseDotNet@2
+        inputs:
+          version: 8.0.x
+
       - task: AzureCLI@2
         displayName: Publish Using Darc
         inputs:

eng/common/core-templates/post-build/post-build.yml

@@ -305,6 +305,11 @@ stages:
 
         - task: NuGetAuthenticate@1
 
+        # Darc is targeting 8.0, so make sure it's installed
+        - task: UseDotNet@2
+          inputs:
+            version: 8.0.x
+
         - task: AzureCLI@2
           displayName: Publish Using Darc
           inputs: