Revocation irma server stops working when upgrading from 0.12.6 to 0.13.0

[ivard]

The revocation server in the irma server of demo.privacybydesign.foundation fails during issuance sessions of revokable credentials with the following error:

Mar 09 10:57:38 37-97-202-140 irma[921]: time="2024-03-09T10:57:38+01:00" level=error msg="Failed to append accumulator update to database" error="sql: Scan error on column index 1, name "data": cbor: cannot unmarshal map into Go value of type irma.signedMessage"

Possibly a migration issue related to one of the changes in #316, #317, #318 or #319.