stop steps if no new versions detected

.github/workflows/vendor.yml

@@ -43,10 +43,12 @@ jobs:
               $updateMessage += "| **$($s.name)** | $oldVersion | **$($s.version)** |`n"
             }
           }
+          if ($count -eq 0) { return }
           Set-GHVariable -Name LIST_UPDATED -Value $listUpdated.Trim(', ')
           echo "UPDATE_MESSAGE<<<EOF`n$updateMessage`n<EOF" | Out-File -FilePath $env:GITHUB_ENV -Append -Encoding utf8
 
     - uses: peter-evans/create-pull-request@v4
+      if: env.COUNT_UPDATED > 0
       with:
         title: 'Updates to `${{ env.COUNT_UPDATED }}` vendored dependencies'
         body: |