In order to run this code, please, add a file called credentials.json. Follow the same format as example.credentials.json.
Then, run go run quickstart.go and check if you can see the expected google-drive.
There are in the code three different ways to apply the credentials.json into the authorization process. These functions are called authByCredentials1(), authByCredentials2(), authByCredentials3().
I think it's enough to try with authByCredentials1(), but if you doubt then use all the options 😄