[gtksourceview/fix/README-deps] README: Update dependency versions

[Mart Raudsepp <mraudsepp src gnome org>]

commit cf377bd2e689a6fff64e4bdb5a159bde75112007
Author: Mart Raudsepp <leio gentoo org>
Date:   Wed Mar 16 18:55:15 2022 +0200

    README: Update dependency versions

 README.md | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/README.md b/README.md
index 62306925..cd31d07d 100644
--- a/README.md
+++ b/README.md
@@ -19,8 +19,8 @@ Nightly documentation can be [found here](https://gnome.pages.gitlab.gnome.org/g
 Dependencies
 ------------
 
-* GLib >= 2.62
-* GTK >= 3.99
+* GLib >= 2.70
+* GTK >= 4.6
 * libxml2 >= 2.6
 * freebidi >= 0.19.7
 * libpcre2-8 >= 10.21