[librsvg/librsvg-2.48] Update NEWS

[Federico Mena Quintero <federico src gnome org>]

commit aea942020c4403e6c50c9722f175c24c3c97b1e0
Author: Federico Mena Quintero <federico gnome org>
Date:   Thu Apr 9 14:15:55 2020 -0500

    Update NEWS

 NEWS | 4 ++++
 1 file changed, 4 insertions(+)
---
diff --git a/NEWS b/NEWS
index 0294f043..c0a99d7e 100644
--- a/NEWS
+++ b/NEWS
@@ -2,6 +2,10 @@ Version 2.48.3
 
 - Librsvg now requires glib 2.50.0 or later.
 
+- rsvg-convert's --background-color option now accepts colors with
+  transparency like #rrggbbaa, rgba(...), hsla(...); the transparency
+  value was ignored before (Hao Guan).
+
 - #584 - Fix arithmetic overflow when rendering to large GdkPixbufs.
 
 - #582 - Make librsvg build with Rust 1.39 again.