How to get pandoc 2+ to retain HTML tags in markdown?

rmd_to_md_pandoc.Rmd

## foo `bar`

hello

```
x <- 5
```

<p align="center">test</p>

I can't figure out how to convert this to markdown using rmarkdown::render() without stripping the `<p>` tag around `test`. (You need to view the "raw" version of this file to see that there is a `<p>` tag, because github renders it as HTML)

rmarkdown::render("test.Rmd", output_format = "md_document", output_options = list(pandoc_args = c("-t", "commonmark"), md_extensions = c("+raw_html", "+raw_attribute")))