That’s a fair question, given that a dishwasher is an electrical appliance, but also needs to be connected to your water. If you’re having a brand-new dishwasher installed that requires the installation of a powerpoint as well, you may need a qualified electrician as well as a qualified plumber.
However, if you’re simply upgrading your old dishwasher to a new model and all the electrical matters have already been taken care of, a licensed plumber should be all that you need.