Curious, as I've stumbled over this one myself - do you have a non-gendered group pronoun you prefer? I feel odd saying "you guys" to mixed groups, but I feel odder with "you all" and "you folks". I've had many female coworkers not care, and others care deeply, but haven't arrived at a solid replacement for "this group I am addressing"
Meh. This is the kind of absurd handwashing that is more about making someone feel better about themselves than actually improving the general situation. The term "you guys" will be heard frequently in pretty much any work environment in the U.S.
I won't pretend to have all the answers, but I can assure you that women aren't avoiding tech because someone said "you guys". Spending 20 minutes with a bunch of cheerleaders should convince you of that.