It's not really a big deal, but I occasionally find myself having to manually delete go.sum files after removing all external dependencies from a project.

Steps to Reproduce

1. Create a project
2. Add an external dependency
3. Execute go mod vendor
4. Note how go.sum has been created
5. Remove the external dependency from the code
6. Execute go mod tidy
7. Note how the go.sum file is now empty.

Conversely, if you had never added an external dependency and executed go mod vendor, go.sum would have never been created, and the following error would have been displayed instead:

go: no dependencies to vendor