I need to fetch the branch a simple checkout only gets all tags

Author: scbedd

eng/common/pipelines/templates/archetype-typespec-emitter.yml

@@ -406,6 +406,7 @@ extends:
                 - Azure
 
           - pwsh: |
+              git fetch origin $(branchName)
               git switch $(branchName)
             displayName: 'Checkout PR branch $(branchName)'