require the dev version of rmarkdown to fix an issue in rmarkdown:::i…

…nput_as_dir (#483)

to get rstudio/rmarkdown@6c5ea83 that should fix one issue described in #481 (pressing Knit triggers an error because RStudio detects "C:" as the project root for some reason when the actual root is in a directory of the C: drive)

DESCRIPTION

@@ -23,7 +23,7 @@ Description: Write blog posts and web pages in R Markdown. This package supports
     supports 'Jekyll' (<https://jekyllrb.com>) and 'Hexo' (<https://hexo.io>).
 License: GPL-3
 Imports:
-    rmarkdown (>= 2.4),
+    rmarkdown (>= 2.4.2),
     bookdown (>= 0.14),
     knitr (>= 1.25),
     htmltools,
@@ -47,3 +47,4 @@ BugReports: https://github.com/rstudio/blogdown/issues
 SystemRequirements: Hugo (<https://gohugo.io>) and Pandoc (<https://pandoc.org>)
 RoxygenNote: 7.1.1
 Encoding: UTF-8
+Remotes: rstudio/rmarkdown