Added tag cubicweb-version-3.18.7, cubicweb-debian-version-3.18.7-1, cubicweb-centos-version-3.18.7-1 for changeset cb96f4403cf2
change_attribute_type('CWCache', 'timestamp', 'TZDatetime')
change_attribute_type('CWUser', 'last_login_time', 'TZDatetime')
change_attribute_type('CWSource', 'latest_retrieval', 'TZDatetime')
drop_attribute('CWSource', 'synchronizing')
add_attribute('CWSource', 'in_synchronization')