update libwebp to 1.2.2 branch (69c7f16)

https://chromium.googlesource.com/webm/libwebp/+log/v1.2.1..69c7f16

- 1/11/2022: version 1.2.2
  This is a binary compatible release.
  * webpmux: add "-set bgcolor A,R,G,B"
  * add ARM64 NEON support for MSVC builds (#539)
  * fix duplicate include error in Xcode when using multiple XCFrameworks in a
    project (#542)
  * doc updates and bug fixes (#538, #544, #548, #550)

Bug: b/202302177
Bug: webp:541
Change-Id: I8269898597d82ccd4c4325914fa5d55fea1affca
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/485616
Reviewed-by: Leon Scroggins <scroggo@google.com>
Commit-Queue: Leon Scroggins <scroggo@google.com>

DEPS

@@ -31,7 +31,7 @@ deps = {
   "third_party/externals/libgifcodec"     : "https://skia.googlesource.com/libgifcodec@fd59fa92a0c86788dcdd84d091e1ce81eda06a77",
   "third_party/externals/libjpeg-turbo"   : "https://chromium.googlesource.com/chromium/deps/libjpeg_turbo.git@24e310554f07c0fdb8ee52e3e708e4f3e9eb6e20",
   "third_party/externals/libpng"          : "https://skia.googlesource.com/third_party/libpng.git@386707c6d19b974ca2e3db7f5c61873813c6fe44",
-  "third_party/externals/libwebp"         : "https://chromium.googlesource.com/webm/libwebp.git@9ce5843dbabcfd3f7c39ec7ceba9cbeb213cbfdf",
+  "third_party/externals/libwebp"         : "https://chromium.googlesource.com/webm/libwebp.git@69c7f16111ec582bf1e7cb4d0d4f8d127e28a715",
   "third_party/externals/microhttpd"      : "https://android.googlesource.com/platform/external/libmicrohttpd@748945ec6f1c67b7efc934ab0808e1d32f2fb98d",
   "third_party/externals/oboe"            : "https://chromium.googlesource.com/external/github.com/google/oboe.git@b02a12d1dd821118763debec6b83d00a8a0ee419",
   "third_party/externals/opengl-registry" : "https://skia.googlesource.com/external/github.com/KhronosGroup/OpenGL-Registry@14b80ebeab022b2c78f84a573f01028c96075553",