Can changing the colour of roofs change the average temperature in a suburb?

Yes, but probably no

If we're feeling a bit pedantic, the answer is obviously yes: a suburb of white roofs will have a higher albedo than one with black roofs. It'll therefore reflect more light instead of absorbing it as heat, resulting in lower temperatures.

The question is whether the change is significant, but it's impossible to give a solid answer to that, since there's an infinity of variables which will change the outcome: how dense is this suburb (if roofs only cover 10% of the area, they'll have a lower impact than if they're 50%), how humid is the air, what's the cloud cover, is it windy, what material are the roofs made of, etc.

That being said, I'd wager the roofs aren't going to have a noticeable impact on the temperature in a suburb, since suburbs tend to be low-density areas, so roofs will be a small fraction of the surface area.

If you're looking for an objective answer, you won't get it without getting your hands dirty with modeling.