cubicweb-oaipmh #14517422 ListIdentifiers : wrong optional and required arguments [validation pending]

metadataPrefix argument must be required. set argument must be optional.

https://www.openarchives.org/OAI/openarchivesprotocol.html#ListIdentifiers

priorityimportant
typebug
done in0.3.0
load left0.000
closed by#ca29756e65a1 Fix ListIdentifiers required/optional arguments
patchFix ListIdentifiers required/optional arguments [applied]