504 demonstrated that several of the CI's are currently failing.
Ensure all CI's are working
The CI system is a mirror of MNE-Python. So a good first step is to look at what changes have recently made to that infrastructure and mirroring the fixes here. E.g. look at their requirements.txt file and the associated PR, check recent changes to their .github directory, check their changes to .circleci directory etc
Do not make fixes outside the scope of fixing the CI's (unless code changes are necessary to fix the CI). If you find any general code improvements or want to add features etc, then open a dedicated PR for that
504 demonstrated that several of the CI's are currently failing.