I saw that update come in yesterday morning as well, but ran into a different problem. I wasn’t able to get the Postfix update UI to accept any keystrokes, mouse clicks etc. It would also not terminate with a ctrl-C. I had to kill the terminal session, which is not normally something I like doing during an apt-get upgrade.
Fortunately that didn’t seem to break anything in Ubuntu, nor Postfix. I put the postfix packages (3 of them) on hold for now with apt-mark.
In the meantime, I found this article about the oddities of postfix updates and terminal sizes. This seems to describe the problem I was experiencing. Hoping it might help others out of the same situation.