Adds support for Keynote 11.2.
Note that between Keynote 10.2 and Keynote 11.2, a number of Protobuf definitions have changed names. `keynote-parser` does not yet support backwards compatibility. (i.e.: it can only read `.key` files as the currently-supported Keynote version would, and will write `.yaml` output with keys that match the current key names - so **`.yaml` files generated with older versions of `keynote-parser` may not be convertible into `.key` or `.iwa` files with this newer version**.)
Until this issue is fixed (_if_ it's ever fixed) - to properly read `.yaml` files created by older versions of `keynote-parser`, use that older version to read the file, write a `.key` (or `.iwa`) file, then read that resulting `.iwa` file in the newer version of `keynote-parser`.