Added go-install installation option

[GhoulKingR]

Fixes issue #231

[diegolikescode]

hey, this is a important one!

I would say that you could add more information based on the golang doc, like "Go 1.18 and beyond doesn't support go get, so you must use go install" or something, but no one ever respond to this PR... come on guys, lets update deeze docs

[GhoulKingR]

Hey @diegolikescode, what if I added that information as code comments in the step 1 code block.

Something like this:

$ go get -u github.com/gin-gonic/gin

# Or

$ go install github.com/gin-gonic/gin@latest

# for Go 1.18 and beyond

You can also check the issue linked to this PR, it says that running the command under go modules works.

[diegolikescode]

@GhoulKingR honestly for me it is good to go, but it must be approved to update te official docs.