Patch release.

This patch reintroduces pugixml target for CMake when find_package is used, which was accidentally removed from v1.11.
It's recommended that pugixml::pugixml target is used instead, but this patch restores pugixml target for existing applications / libraries that depend on it.

The previous patch, v1.11.2, was not compatible with CMake 3.10; this patch restores compatibility with earlier CMake versions when using imported targets.