Pyprt

* Compatible CityEngine versions to create RPKs with: 2021.0 or earlier

Added
* Added pre-built wheels and conda packages for Python 3.9

Changed
* Internal update to [PRT 2.4](https://github.com/Esri/cityengine-sdk/blob/main/changelog.md#cityengine-sdk-247316-changelog) (CityEngine 2021.0)
* Updated compiler requirements on Windows (MSVC 14.27) and Linux (GCC 9.3)
* Updated urllib3, pywin32 and pillow versions in the environment requirements-py3.*.txt files based on dependabot security analysis

Removed
* Removed MacOS support as PRT 2.4 and later is not available anymore on that platform

Added
* New function `get_attributes` on `GeneratedModel`. Returns the CGA rule attributes used to generate the model
* Added support for CGA array attributes
* Added pre-built wheels and conda packages for Python 3.7 and 3.8

Changed
* Updated the `arcgis_to_pyprt` function to work with the latest `arcgis` package (1.8)
* Switched from `pipenv` to `venv` to better support multiple Python versions

Removed
* Removed previously deprecated API functions `inspect_rpk` and overload of `generate_model`
* Removed `tox` to simplify running tests in multiple Python versions

Added
* New `get_rpk_attributes_info(rule_package_path)` function to query CGA rule attributes and their annotations
* Holes and multi faces polygons support in the `arcgis_to_pyprt(...)` function
* PyPRT icon

Changed
* Removal of the overload `generate_model(rule_attributes)` (use `generate_model(rule_attributes, rule_package_path, geometry_encoder, encoder_options)` instead)
* Deprecation of the `inspect_rpk(rule_package_path)` function (use `get_rpk_attributes_info(rule_package_path)` instead)
* Internal update to [PRT 2.3](https://github.com/Esri/cityengine-sdk/blob/main/changelog.md#cityengine-sdk-236821-changelog)
* Updated compiler requirements on Windows (MSVC 14.23)

Fixed
* Removed `streetWidth(a)` attribute from the rule package attributes dictionary (in `inspect_rpk(...)` and `get_rpk_attributes_info(...)`)

Added
* Added new API function `pyprt.inspect_rpk(...)` to query available CGA rule attributes
* Added support for macOS 10.15 (Catalina)
* Added support for initial shapes with polygon holes
* Added automatic detection of RuleFile and StartRule attributes in RPKs
* The `GeneratedModel` class now provides access to CGA `print` and error output when used with the PyEncoder (new `get_cga_prints()` and `get_cga_errors()` functions)

Changed
* Internal update to [PRT 2.2](https://github.com/Esri/cityengine-sdk/blob/main/changelog.md#cityengine-sdk-226332-changelog) (adds support for CGA language features of CityEngine 2020.0)
* Reorganization and cleanup of C++ sources
* Moved PyPRT conda package to Esri organization

Added

* PyPRT conda package available on Anaconda Cloud
* API Documentation
* License file and copyright statements

Changed

* README improvements
* setup.py metadata and PyPI project page improvements

* First public release
* PyPRT wheels available on PyPI
* Published source code on GitHub
* Published [PyPRT examples](https://github.com/Esri/pyprt-examples) on GitHub