Update clap dependency
Rsvg-convert uses clap 2.34.x. The newest clap version is 3.something, and for example, has deprecated clap::App
for clap::Command
.
It would be nice to update this. I don't know if this requires increasing the minimum supported Rust version (MSRV) - currently it is Rust 1.56. We can probably increase that without problems; I'd rather not require the absolute latest stable compiler, but a couple of versions behind is okay.