Set French team as OWNERS (#6821)

Author: MichaelChirico

CODEOWNERS

@@ -45,10 +45,12 @@
 /R/translation.R @michaelchirico
 /src/po.h @michaelchirico
 /po/*.pot @Rdatatable/translators
-/po/*zh_CN.po @Rdatatable/chinese
-/po/*pt_BR.po @Rdatatable/brazil
 /po/*es.po @Rdatatable/spanish
+/po/*fr.po @Rdatatable/french
+/po/*pt_BR.po @Rdatatable/brazil
 /po/*ru.po @Rdatatable/russian
+/po/*zh_CN.po @Rdatatable/chinese
+/vignettes/fr/*.Rmd @Rdatatable/french
 /vignettes/ru/*.Rmd @Rdatatable/russian
 
 # printing