Update model.d.ts (#13514)
Update model.d.ts (#13514)

Add optional `omitNull` flag to the `SaveOptions` interface.

Co-authored-by: Sascha Depold <df3f6e4cf69a28b4d0c05e64fe74fcb2d58ad376@users.noreply.github.com>
sequelize/sequelize,sequelize/sequelize,sequelize/sequelize