fix: better error messages for missing repos

pkg/git/clone.go

@@ -3,6 +3,7 @@ package git
 import (
 	"fmt"
 	"os"
+	"path/filepath"
 	"strings"
 
 	"github.com/go-git/go-git/v5"
@@ -24,6 +25,10 @@ func Clone(dir, url string) error {
 				ReferenceName: plumbing.ReferenceName("refs/heads/main"),
 			})
 			if err != nil {
+				if strings.Contains(err.Error(), "authentication required") {
+					name := filepath.Base(dir)
+					return fmt.Errorf("unable to clone %s, does %s exist?", name, url)
+				}
 				return err
 			}
 		}