So no, there is no appdata or metainfo file in the package, which is
why it does not appear in Gnome Software. File a bug against rstudio
if you want the maintainers to do something about that.
I agree with Jerry - file a request with RStudio. According to the RStudio website they haven't released an updated version since they released rstudio-1.4.1103-x86_64.rpm for Fedora 28.