Fixed for handling exceptions of asgi app call. (#2211)

@cansarigol3megawatt Thanks for looking into this and getting the quick turnaround on this. I will 🍒 pick this into the 21.6 branch and get it out a little later tonight.

sanic/__version__.py

@@ -1 +1 @@
-__version__ = "21.6.1"
+__version__ = "21.6.2"

sanic/asgi.py

@@ -207,4 +207,7 @@ class ASGIApp:
         """
         Handle the incoming request.
         """
-        await self.sanic_app.handle_request(self.request)
+        try:
+            await self.sanic_app.handle_request(self.request)
+        except Exception as e:
+            await self.sanic_app.handle_exception(self.request, e)