add GITHUB_TOKEN environment variable also in code

Author: filipchristiansen

src/gitingest/entrypoint.py

@@ -2,6 +2,7 @@
 
 import asyncio
 import inspect
+import os
 import shutil
 from typing import Optional, Set, Tuple, Union
 
@@ -61,6 +62,9 @@ async def ingest_async(
     """
     repo_cloned = False
 
+    if not token:
+        token = os.getenv("GITHUB_TOKEN")
+
     try:
         query: IngestionQuery = await parse_query(
             source=source,