Feature updates
* `ensure_binary`, `ensure_str` and `assert_regex` utility methods have been migrated from `six.py` to `splunklib/utils.py`
Major changes
* Removed code specific to Python 2
* Removed six.py dependency
* Removed `__future__` imports
* Refactored and Updated `splunklib` and `tests` to utilize Python 3 features
* Updated CI test matrix to run with Python versions - 3.7 and 3.9
* Refactored Code throwing `deprecation` warnings
* Refactored Code violating Pylint rules
Bug fixes
* [527](https://github.com/splunk/splunk-sdk-python/issues/527) Added check for user roles
* Fix to access the metadata "finished" field in search commands using the v2 protocol
* Fix for error messages about ChunkedExternProcessor in splunkd.log for Custom Search Commands