[FIX] packaging: include json files

Some json files are necessary for some modules but are not included in
packaging.

closes odoo/odoo#66759

Signed-off-by: Christophe Monniez (moc) <moc@odoo.com>

MANIFEST.in

@@ -14,6 +14,7 @@ recursive-include odoo *.ico
 recursive-include odoo *.jpeg
 recursive-include odoo *.jpg
 recursive-include odoo *.js
+recursive-include odoo *.json
 recursive-include odoo *.md
 recursive-include odoo *.mp3
 recursive-include odoo *.ogg