adapt to Gtk v0.7

This version has breaking changes to TextView API affecting any methods that take a GtkTextIter

Author: jwahlstrand

Project.toml

@@ -7,7 +7,7 @@ Gtk4 = "9db2cae5-386f-4011-9d63-a5602296539b"
 Markdown = "d6f4376e-aef5-505a-96c1-9c027394607a"
 
 [compat]
-Gtk4 = "0.5, 0.6"
+Gtk4 = "0.7"
 julia = "1.6"
 Markdown = "1.6"
 

src/GtkMarkdownTextView.jl

@@ -1,7 +1,7 @@
 module GtkMarkdownTextView
 
     using Gtk4
-    import Gtk4: _GtkTextIter, create_tag, apply_tag
+    import Gtk4: create_tag, apply_tag
     import Gtk4.GLib: gobject_move_ref, GObject
 
     using Markdown
@@ -71,7 +71,7 @@ module GtkMarkdownTextView
 
     function tag(buffer, what, i, j)
         apply_tag(buffer, what, 
-            _GtkTextIter(buffer, i), _GtkTextIter(buffer, j) 
+            GtkTextIter(buffer, i), GtkTextIter(buffer, j) 
         )
     end