So far, I'm seeing some things on the internet which are homemade interface boxes which convert a 4-pin CB-radio mic plug into something you can then plug into your computer. Such a thing would work for any CB radio mic, not just the D104.

There are two components to such a box: The audio output (sometimes via a 1/8" jack which goes from the box to your computer mic input), and then also the push-to-talk button (via a USB connector going from the box to your computer).

The push-to-talk also requires having software on the computer which takes advantage of the button press (which is usually a USB-serial interface). But the push-to-talk might not be important to you.

I still haven't found a particularly nice and easy pre-made box, most of the stuff I'm seeing is very DIY.