Switch to go mod

vendor/github.com/heroku/docker-registry-client/registry/basictransport.go

@@ -0,0 +1,23 @@
+package registry
+
+import (
+	"net/http"
+	"strings"
+)
+
+type BasicTransport struct {
+	Transport http.RoundTripper
+	URL       string
+	Username  string
+	Password  string
+}
+
+func (t *BasicTransport) RoundTrip(req *http.Request) (*http.Response, error) {
+	if strings.HasPrefix(req.URL.String(), t.URL) {
+		if t.Username != "" || t.Password != "" {
+			req.SetBasicAuth(t.Username, t.Password)
+		}
+	}
+	resp, err := t.Transport.RoundTrip(req)
+	return resp, err
+}