Update setup.md

[milechin]

Updated a few outdated items on this page:

1. The PROJ library is no longer referred to as "proj.4" but rather just "proj". Updated the name and also updated the URLs to point to proj.org rather than proj4.org.
2. Original document refers to the latest version of R as 3.X.X, but currently R 4.2.X is the latest.
3. Rgdal is retiring in 2023, so it not longer should be installed. See : https://r-spatial.org/r/2022/04/12/evolution.html
4. "Terra" is the replacement for raster package and so "raster" should be phased out. See: https://r-spatial.org/r/2022/04/12/evolution.html#packages-depending-on-sp-and-raster

[srappel]

@milechin please see datacarpentry/r-raster-vector-geospatial#368 to see the updates currently in progress in regards to the items you've updated here!

[madelinemberger]

Very small note but I noticed that the raster package is still listed as a key package for this workshop in Episode 4 section titled "GIS in programming languages", rather than terra.

I know this is in progress but just wanted to flag again in case it was missed, because it seems most other workshop and lesson materials all have been updated to terra

[tobyhodges]

@datacarpentry/curriculum-advisors-geospatial I am going to close this because this repository will imminently be transitioned to the new lesson infrastructure (see #66), which will invalidate any open pull requests. Thank you @milechin and @madelinemberger for contributing: I hope we will see updated lesson content and setup instructions soon.

Flagging the DC Geospatial Curriculum Advisors in case they want to discuss this PR and the related thread at datacarpentry/r-raster-vector-geospatial#368 in an upcoming meeting.