Update setup.sh to fix for wget: command not found on mac

[simonsmh]

A stupid fix for wget: command not found on mac
:(
#3590

[mention-bot]

@simonsmh, thanks for your PR! By analyzing the annotation information on this pull request, we identified @kestel and @nivong to be potential reviewers

[bruvv]

this is not how you would do this

[jimmywarting]

Guessing you should do feature detection instead of os detection (like we say on web development)

use wget if it exist
else use curl if it exist

[bruvv]

this is how you would do it:
#3593