chore(main): release python-openinference-instrumentation-langchain 0.1.20

[github-actions[bot]]

:robot: I have created a release beep boop

0.1.20 (2024-06-20)

Bug Fixes

• langchain: message parsing for langgraph (#534) (ccf0683)

---

This PR was generated with Release Please. See documentation.

[github-actions[bot]]

:robot: Release is at https://github.com/Arize-ai/openinference/releases/tag/python-openinference-instrumentation-langchain-v0.1.20 :sunflower: