Webp

- We now bundle libwebp 1.3.2 (formerly 1.0.3) to address CVE-2023-4863. See https://github.com/anibali/pywebp/security/advisories/GHSA-f9pm-4g9p-6vm3. Thanks SCH227.
- We now build binary wheels for Python 3.12. Thanks laggykiller.

This is the first release after migrating from Conan 1.x to 2.0. Usage of the library has not been affected, but it is now easier to build the package and we can make more binary wheels available. Notably, musl builds are available which should be of benefit to Alpine Linux users (see https://github.com/anibali/pywebp/issues/15). We will also be ready to build for Python 3.12 in the future.

Many thanks to laggykiller for key contributions to this release.

This release contains packaging changes which should make it easier for MacOS users to install pywebp (especially on Apple Silicon).

EDIT: The Apple Silicon binaries did not actually build correctly, and will be fixed in the next release.