Macworld With the release of the M3 MacBook Air about a month ago, Apple’s laptop lineup became up-to-date, with each MacBook sporting some version of the M3 chip, the latest in Apple silicon. So, now it should be time for the other shoe to drop: the updates to the desktop Mac lineup. But of the four models in Apple’s desktop Mac lineup, only one has an M3 chip, the iMac. That update came five months ago after a two-year wait, and we don’t even know if the rest of the lines are going to get an update before the M4 arrives. So, what’s going on with Apple’s desktop Macs? Only Apple knows for sur…