update NEWS for 2.7.0

Signed-off-by: Carl Zhang <[email protected]>

NEWS

@@ -1,5 +1,14 @@
-libva NEWS -- summary of user visible changes.  2019-12-25
-Copyright (C) 2009-2019 Intel Corporation
+libva NEWS -- summary of user visible changes.  2020-03-26
+Copyright (C) 2009-2020 Intel Corporation
+
+version 2.7.0 - 26.Mar.2020
+* trace: av1 decode buffers trace
+* trace: Add HEVC REXT and SCC trace for decoding.
+* Add av1 decode interfaces
+* Fix crashes on system without supported hardware by PR #369.
+* Add 2 FourCC for 10bit RGB(without Alpha) format: X2R10G10B10 and X2B10G10R10.
+* Fix android build issue #365 and remove some trailing whitespace
+* Adjust call sequence to ensure authenticate operation is executed to fix #355
 
 version 2.6.0 - 15.Dec.2019
 * enable the mutiple driver selection logic and enable it for DRM.