add await to async call for anonymous sign in request

Author: silentworks

supabase_auth/_async/gotrue_client.py

@@ -165,7 +165,7 @@ async def sign_in_anonymously(
         options = credentials.get("options", {})
         data = options.get("data") or {}
         captcha_token = options.get("captcha_token")
-        response = self._request(
+        response = await self._request(
             "POST",
             "signup",
             body={