在何处以及如何记录项目维护者

As developer, I want to know if there are best practices to put project maintainers inside a Go project.

In php projects this can be done updating composer.json file with content similar to:

{
    "authors": [
        {
            "name": "Name Surname",
            "email": "foo@bar.man",
            "role": "Developer"
        }
    ]
}

Is there a standard Go alternative?

No. Go packages do not track the developer(s) or contributor(s) in any prescribed way.

Of course you can always add them to a README, wiki, code comments, or other human-consumable information as you see fit.