Add Trump to presidential terms dataset (#4702)

Fixes #4703

Author: bkmgit

NEWS.md

@@ -1,5 +1,7 @@
 # ggplot2 (development version)
 
+* `presidential` dataset now includes Trump's presidency (@bkmgit, #4703).
+
 * referring to `x` in backquoted expressions with `label_bquote()` is no longer
   possible.
 

R/data.R

@@ -140,12 +140,13 @@
 #' }
 "msleep"
 
-#' Terms of 11 presidents from Eisenhower to Obama
+#' Terms of 12 presidents from Eisenhower to Trump
 #'
 #' The names of each president, the start and end date of their term, and
-#' their party of 11 US presidents from Eisenhower to Obama.
+#' their party of 12 US presidents from Eisenhower to Trump.  This data is
+#' in the public domain.
 #'
-#' @format A data frame with 11 rows and 4 variables:
+#' @format A data frame with 12 rows and 4 variables:
 #' \describe{
 #'   \item{name}{Last name of president}
 #'   \item{start}{Presidency start date}

data-raw/presidential.R

@@ -1,3 +1,3 @@
 library(readr)
 presidential <- read_csv("data-raw/presidential.csv")
-devtools::use_data(presidential, overwrite = TRUE)
+usethis::use_data(presidential, overwrite = TRUE)

data-raw/presidential.csv

@@ -10,3 +10,4 @@
 "Clinton",1993-01-20,2001-01-20,"Democratic"
 "Bush",2001-01-20,2009-01-20,"Republican"
 "Obama",2009-01-20,2017-01-20,"Democratic"
+"Trump",2017-01-20,2021-01-20,"Republican"