chore: add optional api_base_url to the example

Author: georgeh0

github_code_indexing/main.py

@@ -65,6 +65,8 @@ def github_code_indexing_flow(
  "*.mdx",
  ],
  excluded_patterns=["**/.*", "target", "**/node_modules"],
+ # Optional, can be omitted if using "https://github.com"
+ api_base_url="https://api.github.com",
  )
  )
  code_embeddings = data_scope.add_collector()