[gnome-tweaks] README: Bump required glib to 2.57.2 for per-session overrides

[Jeremy Bicha <jbicha src gnome org>]

commit a58a5980b7932176a849ecee52279f74e82b4550
Author: Jeremy Bicha <jbicha ubuntu com>
Date:   Mon Jul 30 09:44:31 2018 -0400

    README: Bump required glib to 2.57.2 for per-session overrides
    
    See https://gitlab.gnome.org/GNOME/gnome-tweaks/commit/000396a7
    
    This "requirement" is just a strong hint to distro packagers
    so that the GNOME Classic (or Ubuntu or Pop! OS) sessions will
    work correctly.

 README.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/README.md b/README.md
index 43121cc..db49ee3 100644
--- a/README.md
+++ b/README.md
@@ -17,7 +17,7 @@ RUNTIME DEPENDENCIES
 * gnome-settings-daemon
 
 * GIR files and libraries from:
-  - GLib
+  - GLib (>= 2.57.2)
   - GTK+ 3 (>= 3.12)
   - gnome-desktop
   - libsoup