Update gomod and vendor

vendor/github.com/genuinetools/img/client/session.go

@@ -0,0 +1,49 @@
+package client
+
+import (
+	"context"
+	"os"
+
+	"github.com/moby/buildkit/session"
+	"github.com/moby/buildkit/session/auth/authprovider"
+	"github.com/moby/buildkit/session/filesync"
+	"github.com/moby/buildkit/session/testutil"
+	"github.com/pkg/errors"
+)
+
+func (c *Client) getSessionManager() (*session.Manager, error) {
+	if c.sessionManager == nil {
+		var err error
+		c.sessionManager, err = session.NewManager()
+		if err != nil {
+			return nil, err
+		}
+	}
+	return c.sessionManager, nil
+}
+
+// Session creates the session manager and returns the session and it's
+// dialer.
+func (c *Client) Session(ctx context.Context) (*session.Session, session.Dialer, error) {
+	m, err := c.getSessionManager()
+	if err != nil {
+		return nil, nil, errors.Wrap(err, "failed to create session manager")
+	}
+	sessionName := "img"
+	s, err := session.NewSession(ctx, sessionName, "")
+	if err != nil {
+		return nil, nil, errors.Wrap(err, "failed to create session")
+	}
+	syncedDirs := make([]filesync.SyncedDir, 0, len(c.localDirs))
+	for name, d := range c.localDirs {
+		syncedDirs = append(syncedDirs, filesync.SyncedDir{Name: name, Dir: d})
+	}
+	s.Allow(filesync.NewFSSyncProvider(syncedDirs))
+	s.Allow(authprovider.NewDockerAuthProvider(os.Stderr))
+	return s, sessionDialer(s, m), err
+}
+
+func sessionDialer(s *session.Session, m *session.Manager) session.Dialer {
+	// FIXME: rename testutil
+	return session.Dialer(testutil.TestStream(testutil.Handler(m.HandleConn)))
+}