Update module path for correct organization, gofmt code

[thephw]

Changelog

• The organization in github appears to have changed from github.com/xero-github/xoauth to github.com/XeroAPI/xoauth. This updates the package name and imports in the CLI tool to reflect the current organization name.
• Ran gofmt to format code

[JoshBarr]

👍 Thanks @thephw, much appreciated!