There's even a HN post from almost exactly 5 years ago:

Computer Vision: Algorithms and Applications, 2nd ed (szeliski.org)

0 comments

https://news.ycombinator.com/item?id=24945823

But anyway; why not? Yes, add (2020) to the title, by all means.

It is a good thing that links to useful resources like these are reposted every now and then. For many, like myself, this could be the first time seeing it. Perhaps a date tag would add some clarity for those who have already see it.