[gobject-introspection] Update NEWS

[Christoph Reiter <creiter src gnome org>]

commit 7e379314faa78b5a5670477a3d68dd28c1f8a267
Author: Christoph Reiter <reiter christoph gmail com>
Date:   Sun Apr 5 16:12:24 2020 +0200

    Update NEWS

 NEWS | 7 +++++++
 1 file changed, 7 insertions(+)
---
diff --git a/NEWS b/NEWS
index ddcece37..ffe77b8a 100644
--- a/NEWS
+++ b/NEWS
@@ -1,3 +1,10 @@
+1.64.1 - 2020-04-05
+-------------------
+
+* Replace calls to deprecated xml.etree.cElementTree removed in Python 3.9 :mr:`202` (:user:`Stephen 
Gallagher <sgallagher>`)
+* gimarshallingtests: Use g_assert_cmpfloat_with_epsilon. Fixes tests on some architectures :mr:`200` 
(:user:`Iain Lane <iainl>`)
+
+
 1.64.0 - 2020-03-07
 -------------------