Bump openpyxl version
Asked about removal of openpyxl in #2114. While openpyxl<=3.0.10 isn't available when packaging, it turns out that 3.1.2 is. Bumping the version would save quite a bit of time and work and avoid having to repackage openpyxl itself or contact the maintainers.
Not sure if there's anything else using this, but --xlsx seems to work just as expected. No issues there. I think it's fine.
Any breaking change that I may be missing with the new version?
for that matter, why are we pinning openpyxl to not exceed that version?
having a maximum version rather than a minimum can be quite problematic for packaging, as often times only one version is actually available from the repository it would be distributed on