"Drinking alcohol can make it hard for you to think clearly and make good decisions." How Alcohol Can Lower Inhibitions and Cause You to Make Bad Decisions
It makes sense, then, not to drink when you are quitting smoking. That addictive part of your thinking can become more powerful if you do, and it is easier for it to falsely convince you that "just one won't hurt." It always will, maybe not right away, but it always will, lead you to have another, and another until you are right back where you were before you started. That is, smoking and needing to quit.
Don't take the chance. A quit is a terrible thing to lose.