howto needs updated as go get no longer supported

[jlshelby]

$ go get github.com/lib/pq
go: go.mod file not found in current directory or any parent directory.
'go get' is no longer supported outside a module.
To build and install a command, use 'go install' with a version,
like 'go install example.com/cmd@latest'
For more information, see https://golang.org/doc/go-get-install-deprecation
or run 'go help get' or 'go help install'.

[ralfonso-directnic]

This is not an issue for pq, this is because you are not using a module, run go mod init in your code folder and then go get