[librsvg] Update NEWS

[Federico Mena Quintero <federico src gnome org>]

commit 87e8116d13449ff71e7710234529ce946332aa2b
Author: Federico Mena Quintero <federico gnome org>
Date:   Fri Oct 2 13:13:46 2020 -0500

    Update NEWS

 NEWS | 12 ++++++++++++
 1 file changed, 12 insertions(+)
---
diff --git a/NEWS b/NEWS
index 7d0de2d0..c39ae357 100644
--- a/NEWS
+++ b/NEWS
@@ -1,9 +1,21 @@
 Version 2.51.0
 
+- #615: SVG2: Support a chain of uri() filters in the "filter" property
+  (John Ledbetter, Sven Neumann).
+
+- #483: Support CSS selectors for attribute matching, like rect[attr^="prefix"]
+
+- #554: Fixed the geometry_for_layer() APIs to not ignore the passed viewport.
+
+- Fixed CSS "import" so it allows only files from the same base directory
+  (Lars Schmertmann).
+
 - #623 - The pkg-config files (*.pc) do not define the 'svgz_supported' and
   'css_supported' variables anymore.  These variables were hardcoded
   to 'true' and unchanged since 2011.
 
+- #624 - The source repository no longer produces a librsvg-uninstalled.pc file.
+
 Version 2.49.5
 
 - #607 - Support the mix-blend-mode property from SVG2 and the