This has a few fixes to make the CI run.
- There is a problem with a version of
astropy(see https://github.com/astropy/astropy/issues/11093). I've temporarily fixed the version of the dependency that is failing in the ci yml file. This should be removable in the future.
- It looks like
pymc3is pretty broken for python 3.6. There's a problem between the latest version of arviz and pymc3 available as one of the two forgot to make the release explicitly not 3.6 compatible.
- I also added a catch for when pypolychord isn't installed properly the tests won't fall over.