Remove tidyverse from Suggests

[agila5]

I noticed that, at the moment, the package_Suggests_ tidyverse since it's loaded in several vignettes. I think that we could rewrite a small part of those vignettes and remove the (generic) tidyverse dependency since it implies hundreds of useless packages are installed during GHA.

[Robinlovelace]

Sounds reasonable to me.

[luukvdmeer]

I like to use library(tidyverse) in the vignettes such that we can use functions from all tidyverse packages inside examples, without having to explicitly load each individual one. Often I don't even remember if a functions comes from tidyr or dplyr. But am open to have it changed if there is too much unneccessary package loading going on.

[Robinlovelace]

Pros and cons.

Pro: you have the whole tidyverse in there for vignettes.

Con: slower to install on CI (but shouldn't be any slower for most users to install as Suggests are not installed by default).

[luukvdmeer]

I got an email from Hadley politely requesting to remove tidyverse from suggests, so I did that now :)