[librsvg] Update NEWS

[Federico Mena Quintero <federico src gnome org>]

commit 6e6970102759e62236d80b81f7a1df83eb7afd11
Author: Federico Mena Quintero <federico gnome org>
Date:   Mon Jan 21 13:07:08 2019 -0600

    Update NEWS

 NEWS | 7 +++++++
 1 file changed, 7 insertions(+)
---
diff --git a/NEWS b/NEWS
index 7819113f..d3f0f513 100644
--- a/NEWS
+++ b/NEWS
@@ -1,3 +1,10 @@
+Version 2.45.5
+- At build time, you can now pass $CARGO and $RUSTC environment
+  variables if you need to override the default Rust toolchain.
+  Please see COMPILING.md for details.  (Tobias Kortkamp)
+- Fix #405 - In the gdk-pixbuf loader, don't crash the write()
+  function doesn't receive a GError.
+
 Version 2.45.4
 - Brown paper bag release, my apologies.
 - Fix #402 - Fix the library's soname.  Thanks to Gabriele Balducci