this is BS -kinda- microwaves affect the 2.4 Ghz frecuency for wifi, moder access points, routers and clients (cell phones, laptops, etc) use the 5 Ghz frecuency. Also microwaves only affect the wifi if they are really close to the source or destination
So if your wifi is modern enough and you are not sitting next to the microwave, or have the router in your kitchen, you shoud be fine.