First input of urllib.request.urlopen could only be of type 'str' or …

…a Request object. (#89)

* First input of urllib.request.urlopen could only be of type 'str' or a Request object.
Right now, `url` in AsyncExternalDownload is of type dictionary that leads to following error:

AttributeError: 'dict' object has no attribute 'timeout'
See: https://docs.python.org/3/library/urllib.request.html#module-urllib.request

* minor fixes on `async def finish_download`

firecrest/AsyncExternalStorage.py

@@ -229,7 +229,7 @@ async def object_storage_link(self) -> str:
         :calls: GET `/tasks/{taskid}`
         """
         if self._client._api_version > Version("1.13.0"):
-            return await self.object_storage_data["url"]
+            return (await self.object_storage_data)["url"]
         else:
             return await self.object_storage_data
 
@@ -240,7 +240,7 @@ async def finish_download(
 
         :param target_path: the local path to save the file
         """
-        url = await self.object_storage_data
+        url = await self.object_storage_link
         logger.info(f"Downloading the file from {url} and saving to {target_path}")
         # LOCAL FIX FOR MAC
         # url = url.replace("192.168.220.19", "localhost")