Zanshinsdk

* Fixed an issue in the iter_organization_scan_target_scans method that prevented it from ever returning any of the values obtained by the API.
* Fixed several lint warnings.
* Updated test workflows to include Windows and Mac OS X.
* Added automated upload to PyPI Test and PyPI when a new Github release is published.

Fix a bug on Windows systems when installing package. `setup.py` was not forcing utf-8 encoding, leading to installation fail on Windows.

- Change how SDK version works making it compliant with PIP standards
- Update httpx library to fix vulnerability

We're making it possible to pass the Proxy URL via environment variables `HTTP_PROXY` | `HTTPS_PROXY`

- Add support to use Environment Variables to pass credentials to Zanshin SDK.
- Fix `setup.py develop` error missing `httpx` due to circular dependency.

- Add support to use boto3_session along with boto3_profile to method `onboard_scan_target`.