Feat(extension): Added option to enable async workers in Flask and Django

charmcraft/extensions/app.py

@@ -202,6 +202,10 @@ def get_image_name(self) -> str:
         "type": "int",
         "description": "The number of webserver worker processes for handling requests.",
     },
+    "webserver-worker-class": {
+        "type": "str",
+        "description": "The method of webserver worker processes for handling requests. Can be either 'gevent' or 'sync'.",
+    },
 }