Thanks! for this workaround, I only just upgraded 20 to 21 and had exactly the same problem. After editing the Types.php file as you showed, I was able to run occ upgrade on the command line without errors.
Do you have any hints for future updates/upgrades - e.g. my nextcloud instance now recommends I upgrade to 22. Ideally I’d like to get back to a state where files don’t fail the integrity check.
Is there any way to find the offending app/plugin that asks for json_array…
[Just for info: I initially tried just removing facerecognition as suggested in Upgrade from 20 to 21 fails with dbalexception “Unknown column type “json_array” requested” - 
Installation - Nextcloud community but this did not solve the problem in my case → the upgrade failed to complete (perhaps I should have somehow restarted it…)]