Golang docs are out of date

# Description
The Golang doc uses a very old version of the go orb. It should be using the latest, 3.0.2, or at least the same major version. Note that `load-cache` is no longer a command in the latest version of the orb. There may be more things that need to be updated as well.

# Location
https://circleci.com/docs/language-go/

# Steps to Reproduce
N/A