Update webp to 1.3.2

[mattleibow]

Description of Change

Update webp to 1.3.2

Bugs Fixed

• Fixes [BUG] SkiaSharp vendors libwebp vulnerable to CVE-2023-4863 #2608

API Changes

None.

Behavioral Changes

None.

Required skia PR

mono/skia#112

PR Checklist

• Has tests (if omitted, state reason in description)
• Rebased on top of main at time of PR
• Merged related skia PRs
• Changes adhere to coding standard
• Updated documentation

[github-actions]

The backport to release/2.x failed:

The process '/usr/bin/git' failed with exit code 1

To backport manually, run these commands in your terminal:

# Fetch latest updates from GitHub
git fetch
# Create a new working tree
git worktree add .worktrees/backport-release/2.x release/2.x
# Navigate to the new working tree
cd .worktrees/backport-release/2.x
# Create a new branch
git switch --create backport/pr-2622-to-release/2.x
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x --mainline 1 11ad3645be6a1d20576ed1a47f00a9a5667a4006
# Push it to GitHub
git push --set-upstream origin backport/pr-2622-to-release/2.x
# Go back to the original working tree
cd ../..
# Delete the working tree
git worktree remove .worktrees/backport-release/2.x

Then, create a pull request where the base branch is release/2.x and the compare/head branch is backport/pr-2622-to-release/2.x.

[mattleibow]

Backported in #2623