Bump gocui and adapt lazygit code

Original commit message of the gocui change:

This fixes View.Size, Width and Height to be the correct (outer) size of a view
including its frame, and InnerSize/InnerWidth/InnerHeight to be the usable
client area exluding the frame. Previously, Size was actually the InnerSize (and
a lot of client code used it as such, so these need to be changed to InnerSize).
InnerSize, on the other hand, was *one* less than Size (not two, as you would
have expected), and in many cases this was made up for at call sites by adding 1
(e.g. in calcRealScrollbarStartEnd, parseInput, and many other places in the
lazygit code).

There are still some weird things left that I didn't address here:
- a view's lower-right coordinates (x1/y1) are one less than you would expect.
  For example, a view with a 2x2 client area like this:
    ╭──╮
    │ab│
    │cd│
    ╰──╯
  in the top-left corner of the screen (x0 and y0 both zero) has x1/xy at 3, not
  4 as would be more natural.
- a view without a frame has its coordinates extended by 1 on all sides; to
  illustrate, the same 2x2 view as before but without a frame, sitting in the
  top-left corder of the screen, has coordinates x0=-1, y0=-1, x1=2, y1=2. This
  is highly confusing and unexpected.

I left these as they are because they would be even more of a breaking change,
and also because they don't have quite as much of an impact on general app code.

vendor/github.com/jesseduffield/gocui/gui.go

@@ -912,7 +912,7 @@ func calcScrollbarRune(
 }
 
 func calcRealScrollbarStartEnd(v *View) (bool, int, int) {
-	height := v.InnerHeight() + 1
+	height := v.InnerHeight()
 	fullHeight := v.ViewLinesHeight() - v.scrollMargin()
 
 	if v.CanScrollPastBottom {