How to fix a squeaky electrical dryer
This is probably due to a bad or unlubricated drum roller. Look up the service manual for your dryer to get access to these rollers, but a generic diagram is below.



Note that many dryer drums are not suspended from the center, but rather rest on a few rollers, front and back, beneath the drums. If there's friction in the roller, it might not contact the drum for the whole rotation but makes periodic, squeaky, contact.

Inspect the rollers. If the rubber wheel is deteriorated, a replacement roller and belt kit might be about US$40, depending on dryer model, or look for just individual rollers. If the wheels look good, you could apply one or two drops of motor oil to the shafts. Caution: oil, lint and heat can lead to a fire, so vacuum the dryer thoroughly, and be sparing with the oil, which could also destroy the rubber belt.

If the dryer is more than a few years old, I'd suggest getting the correct roller replacement kit, rather than an individual roller, whatever the condition of the roller wheels, replacing only the bad one(s), keeping the rest until another breaks.