chore: Update SDK version to 0.13.0#217

Abhijeet Prasad (AbhiPrasad) wants to merge 1 commit intomainbraintrustdata/braintrust-sdk-python:mainfrom

abhi-0.13.0-version-bumpbraintrustdata/braintrust-sdk-python:abhi-0.13.0-version-bumpCopy head branch name to clipboard