Update genpdf-rs to v0.2.0

Update genpdf-rs to v0.2.0-alpha.0

Activate all features for PDF generation

We also want to demonstrate hyphenation in the demo PDF document, so we
have to activate all features.

Pin genpdf-rs version in .build.yml

As we always want to build the demo file for the latest release, we pin
the genpdf-rs version in the build script.

Initial commit