pkgdown with a Quarto vignette generates unwanted `vignettes/.quarto`

[friendly]

In my {candisc} package I introduced a new vignette, written as a Quarto .qmd file. It all looks good, except that when I run devtools::check_win_release(), I get a NOTE,

* checking for hidden files and directories ... NOTE
Found the following hidden files and directories:
  vignettes/.quarto
These were most likely included in error. See section 'Package
structure' in the 'Writing R Extensions' manual.

CRAN-pack does not know about
  vignettes/.quarto

I think this is created if I click on Render to view the current vignette.
I added that folder to my .Rbuildignore, but that doesn't seem to help. My current work-around is just to delete that folder, and then win-builder is happy.