chor: upgrade to latest zig; remove zg dependency

src/app.zig

@@ -1,5 +1,9 @@
 //! Application type for TUI-applications
 
+// FIX known issues:
+// - reseting the terminal screen when stopping an `App` under `tmux`
+//   (outside of tmux it seems to work, and other applications can also do that)
+
 /// Create the App Type with the associated user events _E_ which describes
 /// an tagged union for all the user events that can be send through the
 /// applications event loop.
@@ -376,8 +380,8 @@ pub fn App(comptime E: type) type {
                             },
                             0x7f => .{ .cp = input.Backspace },
                             else => {
-                                var iter = code_point.Iterator{ .bytes = buf[0..read_bytes] };
-                                while (iter.next()) |cp| this.postEvent(.{ .key = .{ .cp = cp.code } });
+                                var iter: std.unicode.Utf8Iterator = .{ .bytes = buf[0..read_bytes], .i = 0 };
+                                while (iter.nextCodepoint()) |cp| this.postEvent(.{ .key = .{ .cp = cp } });
                                 continue;
                             },
                         };
@@ -431,7 +435,6 @@ const fmt = std.fmt;
 const posix = std.posix;
 const Thread = std.Thread;
 const assert = std.debug.assert;
-const code_point = @import("code_point");
 const event = @import("event.zig");
 const input = @import("input.zig");
 const terminal = @import("terminal.zig");