DOC: Add Golang 1.18 synax

[neverping]

On Golang 1.18 and newer, we must pass the version we want to install, such as latest. Otherwise it doesn't work.

$ go install github.com/globocom/prettylog
go: 'go install' requires a version when current directory is not in a module
	Try 'go install github.com/globocom/prettylog@latest' to install the latest version
$ go version
go version go1.20.7 darwin/arm64