Fix summary task

Author: hallipr

eng/pipelines/templates/stages/archetype-autorest-preview.yml

@@ -496,11 +496,11 @@ stages:
           -PRLabels 'Do Not Merge'
 
     - pwsh: |
-        $markdownSummary = @"
+        $summaryPath = "$(System.DefaultWorkingDirectory)/summary.md"
+        $summaryMarkdown = @"
           **PR:** [Azure/$(sdkRepositoryName)#$(Submitted.PullRequest.Number)](https://github.com/Azure/$(sdkRepositoryName)/pull/$(Submitted.PullRequest.Number))
           **Title:** $(PullRequestTitle)
         "@
-
-        $markdownSummary | Out-File "$(System.DefaultWorkingDirectory)/summary.md"
-        Write-Host "##vso[task.addattachment type=Distributedtask.Core.Summary;name=Pull Request Created;)/summary.md"
+        $summaryMarkdown | Out-File $summaryPath
+        Write-Host "##vso[task.addattachment type=Distributedtask.Core.Summary;name=Pull Request Created;]$summaryPath"
       displayName: Write PR Data to build summary