This commit adds cumulated optional attribute to the graph view rng
definition.
`cumulated` graph attribute is used, defined and tested in PR #97394.
closesodoo/odoo#111880
X-original-commit: 5be91c78c687cc2ac8fd3f9a94e4e8ef2b951efa
Signed-off-by: Dardenne Florent (dafl) <dafl@odoo.com>