fix: update GitPython constraint for security fix (#423)

## Summary
- Require GitPython >= 3.1.50 to pick up the security fix for Dependabot
alert 118
- Refresh uv.lock for the patched GitPython release
- Also includes the lockfile-only langchain-core patch release update
needed for Dependabot alert 117

Author: AbhiPrasad

py/pyproject.toml

@@ -18,7 +18,7 @@ classifiers = [
     "Operating System :: OS Independent",
 ]
 dependencies = [
-    "GitPython",
+    "GitPython>=3.1.50",
     "requests",
     "chevron",
     "tqdm",