fix import paths

Author: rok

dev/update_stub_docstrings.py

@@ -27,9 +27,13 @@
 import argparse
 import importlib
 import inspect
+import sys
 from pathlib import Path
 from textwrap import indent
 
+# Add current directory to path to find locally built pyarrow
+sys.path.insert(0, ".")
+
 import libcst
 from libcst import matchers as m