[FIX] packaging: bump win installer version

Quick fix that need to be automated.

Closes #77981

closes odoo/odoo#77988

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

setup/win32/setup.nsi

@@ -43,7 +43,7 @@ Unicode True
 !define PUBLISHER 'Odoo S.A.'
 
 !ifndef MAJOR_VERSION
-    !define MAJOR_VERSION '14'
+    !define MAJOR_VERSION '15'
 !endif
 
 !ifndef MINOR_VERSION