[gtksourceview] build: bump GTK required version to 4.5

[Christian Hergert <chergert src gnome org>]

commit cf7f571ca2421c97e95bd895948efc0757b0698d
Author: Christian Hergert <chergert redhat com>
Date:   Wed Feb 2 13:27:05 2022 -0800

    build: bump GTK required version to 4.5

 meson.build | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/meson.build b/meson.build
index 10eb723f..5335cee7 100644
--- a/meson.build
+++ b/meson.build
@@ -69,7 +69,7 @@ build_gtk_doc = get_option('gtk_doc')
 cc = meson.get_compiler('c')
 
 glib_req_version = '2.70'
-gtk_req_version = '4.4'
+gtk_req_version = '4.5'
 
 libm_dep = cc.find_library('m', required: false)