Bump gocui

... and switch back from stefanhaller's tcell fork to the official tcell. This
basically reverts 7ccb871a45.

vendor/github.com/gdamore/tcell/v2/tscreen_unix.go

@@ -0,0 +1,32 @@
+// Copyright 2021 The TCell Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use file except in compliance with the License.
+// You may obtain a copy of the license at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//go:build aix || darwin || dragonfly || freebsd || linux || netbsd || openbsd || solaris || zos
+// +build aix darwin dragonfly freebsd linux netbsd openbsd solaris zos
+
+package tcell
+
+// initialize is used at application startup, and sets up the initial values
+// including file descriptors used for terminals and saving the initial state
+// so that it can be restored when the application terminates.
+func (t *tScreen) initialize() error {
+	var err error
+	if t.tty == nil {
+		t.tty, err = NewDevTty()
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}