Updated drupal/stage_file_proxy

Author: stephen-cox

composer.json

@@ -33,7 +33,7 @@
         "drupal/rabbit_hole": "^1.0@beta",
         "drupal/redirect": "^1.6",
         "drupal/responsive_menu": "^4.4",
-        "drupal/stage_file_proxy": "^2.0",
+        "drupal/stage_file_proxy": "^3.1",
         "drupal/upgrade_status": "^4.0",
         "drupal/varnish_purge": "^2.1",
         "drupal/webform": "^6.2@RC",