Changed method implementation

Author: vladvildanov

redis/credentials.py

@@ -53,6 +53,4 @@ def get_credentials(self):
         return (self.password,)
 
     async def get_credentials_async(self) -> Union[Tuple[str], Tuple[str, str]]:
-        if self.username:
-            return self.username, self.password
-        return (self.password,)
+        return self.get_credentials()