longer server shutdown timeout

Author: Archmonger

src/reactpy/testing/backend.py

@@ -138,7 +138,7 @@ async def __aexit__(
             msg = "Unexpected logged exception"
             raise LogAssertionError(msg) from logged_errors[0]
 
-        await asyncio.wait_for(self.webserver.shutdown(), timeout=20)
+        await asyncio.wait_for(self.webserver.shutdown(), timeout=30)
 
     async def restart(self) -> None:
         """Restart the server"""