Fixed references to a v3 directory that no longer exists in the repo

[mjiori]

This PR fixes up references to a v3 directory that no longer exists in this repo, preventing code from building.
I also added a note to DevelopingDART about running wails build before testing and fixed up some list numbers.

All tests pass.

[diamondap]

I can't approve these changes. v3 is actually the package version number, not a folder name. If you look in go.mod, you'll see the name of the package is module github.com/APTrust/dart/v3. You'll also see we include Wails v2 as github.com/wailsapp/wails/v2 v2.10.2 and Minio as github.com/minio/minio-go/v7. We reference those packages the same way when we include them in go files, as we do for Minio at

dart/scripts/s3_helper.go

Line 17 in 594f342

"github.com/minio/minio-go/v7/pkg/credentials"

.

I want to keep the current package version. I'm not sure why you can't run the tests without these changes. They run on Mac, Linux and Windows for me. Is there some other problem with your setup?

[mjiori]

My bad, I was working under a mistaken assumption.

I got the tests to work without these changes. The real solution for me was to run:
go get github.com/APTrust/dart/v3/dart
go get github.com/APTrust/dart/v3/server

I'll add this to the documentation, and I will close this PR and open a new one to do that.