Use only free fonts in the samples

[notgull]

piet/piet/src/samples/picture_0.rs

Line 21 in 24acaf6

let georgia = rc.text().font_family("Georgia").ok_or(Error::MissingFont)?;

On my Linux machine, I don't have the "Georgia" font installed because I avoid installing any non-free packages. It would be nice if this sample had an alternative font that was free.

[xStrom]

Is there a specific free font you have in mind which exist on Windows/macOS/Linux?

If such a font doesn't exist then I guess for this example it wouldn't be a big problem to choose a different font for the cairo backend.

[cmyr]

The samples are intended to be run during CI, and so reproducibility is important (so we want a named font, and not something like "generic system serif".) I agree it would be nice to be using free fonts, but I'd also prefer not to be bundling font files, so I'm not sure of a great solution, here?