Use inbuilt pipe in chapter 6.3

[sebffischer]

One could use |> instead of %>% in chapter 6.3.
This also removes the argument against the pipe relying as relying on another library.

[MichaelChirico]

I don't think %>% has to be removed, but certainly we can mention the native pipe now. This paragraph is dated:

Piping, x %>% f() %>% g(), allows you to read code in straightforward left-to-right fashion and doesn’t require you to name intermediate objects. But you can only use it with linear sequences of transformations of a single object. It also requires an additional third party package and assumes that the reader understands piping.