Fix bug related to precipitation calculation

Precipitation was reported to be in mm in this package, but was only
converted to cm. This fixes that bug. Units for precipitation are now
reported in mm.

R/get_GSOD.R

@@ -402,7 +402,7 @@ get_GSOD <- function(years = NULL, station = NULL, country = NULL, path = "",
                     NA_integer_)
   tmp$MIN <- ifelse(!is.na(tmp$MIN), round( (tmp$MIN - 32) * (5 / 9), 2),
                     NA_integer_)
-  tmp$PRCP <- ifelse(!is.na(tmp$PRCP), round( (tmp$PRCP * 25.4) * 10, 1),
+  tmp$PRCP <- ifelse(!is.na(tmp$PRCP), round( (tmp$PRCP * 25.4) * 100, 1),
                      NA_integer_)
   tmp$SNDP <- ifelse(!is.na(tmp$SNDP), round( (tmp$SNDP * 25.4) * 10, 1),
                      NA_integer_)