Update CHANGELOG

Bug: aomedia:3515
Change-Id: I456b5a3d9df43a5da57b78ef3c59762af85a6758

CHANGELOG

diff --git a/CHANGELOG b/CHANGELOG
index aa1a630..5cd6634 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,4 +1,4 @@
-2023-11-21 v3.8.0
+2023-11-23 v3.8.0
   This release includes new codec interfaces, compression efficiency and
   perceptual improvements, speedup and memory optimizations and many bug
   fixes. This release is ABI compatible with the last release.
@@ -15,6 +15,18 @@
       for standard bitdepth live-stream and VoD encoding: up to 10% and
       20% respectively, over the Armv8.0-A baseline build.
 
+  - Speedup and Memory Optimizations
+    * Good-quality, single-thread encoder speedups:
+      o 15% improvement for speed 5
+      o 12% improvement for speed 6
+
+  - Bug Fixes
+    * Fixes to improve libaom stability in case of memory allocation
+      failures.
+    * Fixes to SIMD functions (x86 AVX2/SSE2 and ARM Neon).
+    * b/310457427, b/310766628: Bug fixes to only use rec_sse in CBR
+      mode.
+
 2023-11-17 v3.7.1
   This release includes several bug fixes. This release is ABI
   compatible with the last release. See