From @Todd Gayley's tutorial here, you're supposed to be able to set Updating -> Automatic in PacletInfo.wl and the Paclet will update automatically. However, I found your post because that has not been my experience. Since this is a 3 year old post, did you get an answer to your question?
Just to clarify, if I've deployed MyPaclet I expect to be able to do
Get["MyPaclet`"]
And have the server detect a new version is available and download it (assuming the version number has incremented)
