Release 0.3.0 on GH as well

[DrRuhe]

You released 0.3.0 back in january: #14 (comment)

I noticed that 0.3.0 is published on crates.io, but not published on GH-releases (and thus, it did not propagate to the nixpkgs registry). Additionally, the Cargo.toml still says 0.2.0.

Thanks in advance :)

[DrRuhe]

I also notice that the -V/--version CLI argument is missing from 0.3.0

[dzfranklin]

Good catch !