Update CHANGELOG, CMakeLists.txt for libaom v3.9.1

Bug: aomedia:3577
Change-Id: Iaefb89ddb6fe2bb077c813b3f7c19b86a447a350

CHANGELOG

diff --git a/CHANGELOG b/CHANGELOG
index 96a8efb..215e176 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,3 +1,25 @@
+2024-05-30 v3.9.1
+  This release includes several bug fixes. This release is ABI
+  compatible with the last release. See
+  https://aomedia.googlesource.com/aom/+log/v3.9.0..v3.9.1 for all the
+  commits in this release.
+
+  - Bug Fixes
+    * aomedia:2754, aomedia:3567: Ensure thread stack size is at least
+      256 KB
+    * b:330639949, oss-fuzz:68195: Increase scaling in linsolve_wiener
+    * Fix high target data rate overflow.
+    * aomedia:3509: Fix two UBSan errors in av1_rc_update_framerate()
+    * aomedia:3382, chromium:339877165: update codec config after
+      svc/scale controls (CVE-2024-5493)
+    * aomedia:3571: {,highbd_}intrapred_neon.c: Avoid over-reads in z1
+      and z3 preds
+    * oss-fuzz:68774: libaom:av1_dec_fuzzer: Segv on unknown address in
+      od_ec_dec_init
+    * Arm SVE build fixes.
+    * av1_block_error_lp_neon: fix block_size param type
+    * av1_block_error_lp_sve: fix block_size param type
+
 2024-04-09 v3.9.0
   This release includes new codec interfaces, compression efficiency and
   perceptual improvements, speedup for RTC for both video and screen content,

CMakeLists.txt

diff --git a/CMakeLists.txt b/CMakeLists.txt
index ab8935f..d423fab 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -59,7 +59,7 @@
 #
 # We set SO_FILE_VERSION = [c-a].a.r
 set(LT_CURRENT 12)
-set(LT_REVISION 0)
+set(LT_REVISION 1)
 set(LT_AGE 9)
 math(EXPR SO_VERSION "${LT_CURRENT} - ${LT_AGE}")
 set(SO_FILE_VERSION "${SO_VERSION}.${LT_AGE}.${LT_REVISION}")