Since commit bbb1a8f1, module's upgrade script can also be added
into special 'upgrades' folder as an alternative to the old 'migrations'
folder.

  As those upgrade scripts are not maintained from version to version, we
should not count them as maintenance.

OPW-2536046

closes odoo/odoo#76315

X-original-commit: 28a303a6
Signed-off-by: Xavier Alt (xal) <xal@odoo.com>