No version pinning required for pint with Python 3.9 or higher

Python versions starting from 3.9 will install, by default, the newer pint 0.22. This pint version does not have the problems observed in pint 0.21.1. This means that installation of the vre-language with python >=3.9 would no longer require version pinning of any package.

Currently Python 3.9 is not employed because the docker container used for the CI pipeline uses Python 3.8.

• Full support for Python 3.9, including upgrading the docker container for CI, should be addressed.
• An additional request is to include in the CI pipeline tests for the creation of virtual environments with the conda create or python -m venv methods.