Update to libaom v3.12.1

CHANGELOG.md

diff --git a/CHANGELOG.md b/CHANGELOG.md
index d2374f1..7196858 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -27,8 +27,7 @@
   ImageMirror property, and carries an Exif chunk. Note that Exif orientation is
   usually ignored in PNG files, so this mainly impacts JPEG files.
 * Allow lowercase GUIDs in XMP when reading JPEG files.
-* Update aom.cmd/LocalAom.cmake: v3.12.0-4-g65ddc22823. This fixes an encode &
-  decode issue on PowerPC (ppc64le).
+* Update aom.cmd/LocalAom.cmake: v3.12.1
 * Change avifenc to start in automatic tiling mode.
 * Always forward Unspecified (2) CICP color primaries, transfer characteristics,
   and matrix coefficients to the AV1 encoder. Rely on the 'colr' box instead.

cmake/Modules/LocalAom.cmake

diff --git a/cmake/Modules/LocalAom.cmake b/cmake/Modules/LocalAom.cmake
index c5c22dd..ec05b3a 100644
--- a/cmake/Modules/LocalAom.cmake
+++ b/cmake/Modules/LocalAom.cmake
@@ -1,4 +1,4 @@
-set(AVIF_AOM_GIT_TAG v3.12.0-4-g65ddc22823)
+set(AVIF_AOM_GIT_TAG v3.12.1)
 set(AVIF_AVM_GIT_TAG research-v9.0.0)
 
 if(AVIF_CODEC_AVM)

ext/aom.cmd

diff --git a/ext/aom.cmd b/ext/aom.cmd
index f7f0944..13193f6 100755
--- a/ext/aom.cmd
+++ b/ext/aom.cmd
@@ -8,8 +8,7 @@
 : # If you're running this on Windows, be sure you've already run this (from your VC2019 install dir):
 : #     "C:\Program Files (x86)\Microsoft Visual Studio\2019\Professional\VC\Auxiliary\Build\vcvars64.bat"
 
-git clone https://aomedia.googlesource.com/aom
-git -C aom checkout v3.12.0-4-g65ddc22823
+git clone -b v3.12.1 --depth 1 https://aomedia.googlesource.com/aom
 
 cmake -G Ninja -S aom -B aom/build.libavif -DBUILD_SHARED_LIBS=OFF -DCONFIG_PIC=1 -DCMAKE_BUILD_TYPE=Release -DENABLE_DOCS=0 -DENABLE_EXAMPLES=0 -DENABLE_TESTDATA=0 -DENABLE_TESTS=0 -DENABLE_TOOLS=0
 cmake --build aom/build.libavif --config Release --parallel