Sammo

- costs are now correctly retrieved from cached requests
- small bug in plotting fixed

Visualize the execution trace as well as the static program graph now via `.plot_call_trace()` and `.plot_program()`.

What's Changed
* Plotting + tutorials update by t-schn in https://github.com/microsoft/sammo/pull/36
**Full Changelog**: https://github.com/microsoft/sammo/compare/0.1.8...0.2.0

Now possible via optimizer.save().

SAMMO should now run on Python 3.9 and 3.10 as parts of asyncio have been backported.

Embeddings are now cached via a SQLite database on an instance basis. This avoids having to call endpoints repeatedly if batch ordering differs.