We are trying to figure out an answer to that right now.
What we have heard is that in addition to the version 8 format .speclib file that you are seeing there is also supposed to be another file whose name ends in ".skyline.speclib", but we have not yet figured out how that file is supposed to be created when you run dia-nn.
The latest DIA-NN user interface does have a "Skyline" button, which we have determined only works if you have the latest Skyline-daily administrator version installed which you can install from here:
https://skyline.ms/wiki/home/software/Skyline/daily/page.view?name=install-administrator-64
Hopefully we will have an answer in a day or two.
-- Nick