Can't pass custom CSS to blastula_email()

[rjake]

I can pass CSS by adding <style>....</style> to my rmd but when I try to pass a css argument via ..., I get this error

blastula::blastula_email(css = "https://maxcdn.bootstrapcdn.com/bootstrap/3.4.1/css/bootstrap.min.css")
# Error in rmarkdown::html_document(toc = toc, toc_depth = toc_depth, toc_float = toc_float,  : 
# formal argument "css" matched by multiple actual arguments

It seems to be due to a hardcoded CSS parameter here but not in the formal args list: https://github.com/rstudio/blastula/blob/e834f5369d86d373ccecc5fad61f1ea55d00a80a/R/blastula_email_format.R#L117