Update PTY start call sites

cmd/spike/main.go

@@ -108,7 +108,7 @@ func run(argv []string, cols, rows uint16, idleMS int, followHost, stdinPassthro
 	}
 	defer em.Close()
 
-	child, err := pty.Start(argv, nil, cols, rows)
+	child, err := pty.Start(argv, nil, "", cols, rows)
 	if err != nil {
 		return fmt.Errorf("pty: %w", err)
 	}