How do I cite CVPR workshop conference "short" paper?
Clearly.
The main purpose of a bibliography entry is to properly identify the work, with enough information that (at least in principle) your readers can find the work and read it for themselves.  If the github.io repository doesn't suggest a citation format, make up something reasonable that serves that purpose.  The precise formatting doesn't matter (or if it does, the editor will fix it for you).  For example:

[10] J. Smith and R. Tyler.  BADWOLF: A temporally agnostic relational
database information system.  Presented at the 13th Gallifreyan
Workshop on Untempered Schismatics, Arcadia, December 2020.
https://torchwood.github.io/badworf.pdf