Version numbers have the format <major>.<minor>.<subminor>, like 0.9.2.
This function compares the current version number of ggplot2 against the
specified version, which is the most recent version before the
function (or other object) was deprecated.
gg_dep(version, msg)The last version of ggplot2 where this function was good (in other words, the last version where it was not deprecated).
The message to print.
gg_dep will give an error, warning, or message, depending on the
difference between the current ggplot2 version and the specified
version.
If the current major number is greater than version's major number,
or if the current minor number is more than 1 greater than version's
minor number, give an error.
If the current minor number differs from version's minor number by
one, give a warning.
If the current subminor number differs from version's subminor
number, print a message.