dev-R/*: add upstream metadata

Signed-off-by: Alessandro Barbieri <lssndrbarbieri@gmail.com>

dev-R/stringr/metadata.xml

@@ -16,5 +16,7 @@ one function is easy to feed into the input of another.</longdescription>
 			<name>Hadley Wickham</name>
 			<email>hadley@rstudio.com</email>
 		</maintainer>
+		<bugs-to>https://github.com/tidyverse/stringr/issues</bugs-to>
+		<remote-id type="github">tidyverse/stringr</remote-id>
 	</upstream>
 </pkgmetadata>