Dublin Core serializer needs update

[jma]

Describe the bug

serialize_oaipmh serializer (

invenio-records-rest/invenio_records_rest/serializers/dc.py

Line 56 in 82dc6e0

def serialize_oaipmh(self, pid, record):

) causes a crash of invenio-oaiserver.

invenio-oaiserver has been change, the serializer is called with a python dict instead of a Record instance.

This serializer should be updated in a similar way than invenio-rdm: https://github.com/inveniosoftware/invenio-rdm-records/blob/89e63fe293a28204f678a0de81f2e2614943b800/invenio_rdm_records/resources/serializers/dublincore/__init__.py#L36