fix: Handle empty stargazers (#192)

* Fix stargazers empty

* Have to convert to list first

tap_github/repository_streams.py

@@ -1603,8 +1603,11 @@ def get_next_page_token(
         # If since parameter is present, try to exit early by looking at the last "starred_at".
         # Noting that we are traversing in DESCENDING order by STARRED_AT.
         if since:
-            results = extract_jsonpath(self.query_jsonpath, input=response.json())
-            *_, last = results
+            results = list(extract_jsonpath(self.query_jsonpath, input=response.json()))
+            # If no results, return None to exit early.
+            if len(results) == 0:
+                return None
+            last = results[-1]
             if parse(last["starred_at"]) < parse(since):
                 return None
         return super().get_next_page_token(response, previous_token)