[gnome-software] gtk-style.css: Add outline radius for round button

[Kalev Lember <klember src gnome org>]

commit 36b4a6f6d15b10bafac98a65124fb70240a3e783
Author: monday <monday15 gmx com>
Date:   Sat Dec 22 06:54:59 2018 +0000

    gtk-style.css: Add outline radius for round button
    
    Add missing outline radius for expander round button.
    
    Closes https://gitlab.gnome.org/GNOME/gnome-software/issues/558

 src/gtk-style.css | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/src/gtk-style.css b/src/gtk-style.css
index ef7168dd..283efb9c 100644
--- a/src/gtk-style.css
+++ b/src/gtk-style.css
@@ -51,6 +51,7 @@
 
 .round-button {
        border-radius: 16px;
+       -gtk-outline-radius: 16px;
 }
 
 .details-license-free,