add an echo so we can save the output of the pr number

.github/workflows/sage-test.yml

@@ -37,7 +37,7 @@ jobs:
           esac
 
           php_short=$(echo "${{ matrix.php-version }}" | tr -d '.')
-          pr_num="${{ github.event.number }}"
+          pr_num=$(echo "${{ github.event.number }}")
 
           multidev_name="${os_short}-${php_short}-${pr_num}"
           echo "Generated multidev name: $multidev_name"