PYPI version out of date

[drice]

Summary

These docs https://amplitude.com/docs/sdks/experiment-sdks/experiment-python and the readme instruct to use pip install amplitude-experiment, but the PYPI version hasn't been updated in ~1 year.

[tyiuhc]

@drice Many thanks for raising this issue. We are currently working on addressing this, in the meantime, pip install git+https://github.com/amplitude/experiment-python-server.git can be used to install the most recent versions of our SDK.