Cad-to-openmc

Minor update release fixing a few bugs.
- Adds a warning for known problematic geometries, such as degenerate toroids.
- Streamlined package building
- Available on conda

What's Changed
* Merge assemblies by ebknudsen in https://github.com/openmsr/CAD_to_OpenMC/pull/90


**Full Changelog**: https://github.com/openmsr/CAD_to_OpenMC/compare/v0.3.1...v0.3.2

CAD_to_OpenMC v 0.3.1 is a respin-release of 0.3.0 which contains an improved hash-collision protection algorithm
Other highlights:
- supports setting the implicit complement
- inclusion into the model-benchmark-zoo project: https://github.com/fusion-energy/model_benchmark_zoo
- automatic testing of OpenMC-neutronics using github actions
- passes the godiva-benchmark test on par with cubit.
- inclusion of a utility runscript with a set of command line flags.
.. among many other improvements and bugfixes.

This is a respin release of 0.2 to correct for a newly discovered change in the upstream dependencies of CAD_to_OpenMC. Apparently cadquery2 can no longer be installed using pip. Therefore we have had to revert to an older version of cadquery for the time being. This should not create any problems.

This is the first release of the CAD_to_OpenMC tool. At present it works well with simpler geometries, such the 7-pin geometry included with the release, and in cases for full scale reactor geometries. An instance of the latter is the ZPRE-model which can easily run neutronics "out-of-the-box". This model can be found at https://www.github.com/openmsr/zpre - on the "open"-branch.

As a release this should be considered work in progress. We aim at publishing more reactors models and meshing parameters as soon as they become available.