0.59.0

• When using piccolo asgi new to generate a FastAPI app, the generated code is now cleaner. It also contains a conftest.py file, which encourages people to use piccolo tester run rather than using pytest directly.
• Tidied up docs, and added logo.
• Clarified the use of the PICCOLO_CONF environment variable in the docs (courtesy @theelderbeever).
• create_pydantic_model now accepts an include_columns argument, in case you only want a few columns in your model, it's faster than using exclude_columns (courtesy @sinisaos).
• Updated linters, and fixed new errors.