SparkR CRAN check gives a warning with R 4.0.0 on OSX

When the SparkR package is run through a CRAN check (i.e. with something like R CMD check --as-cran ~/Downloads/SparkR_2.4.6.tar.gz), we rebuild the SparkR vignette as a part of the checks.

However this seems to be failing with R 4.0.0 on OSX – both on my local machine and on CRAN https://cran.r-project.org/web/checks/check_results_SparkR.html

cc Felix Cheung