odoo/upgrade-util#306

Created by Upgrade, Christophe Simonis (chs)

Blocked

label
odoo-dev:master-convert_many2one_field_to_many2many-chs
head
10c246ac8c6b3d89a466a5a4fd175a583f4b01ee
odoo/upgrade-util
master #306 missing r+

[ADD] util.convert_many2one_field_to_many2many

TODO:
- write doc
- tests