[doc] update copyright

Cargo.toml

src/bases/b16.rs

src/bases/b58.rs

src/bases/b64.rs

src/bases/mod.rs

src/hashs/mod.rs

src/keys/bin_signable.rs

src/keys/ed25519.rs

src/keys/mod.rs

src/keys/text_signable.rs

src/lib.rs

src/rand.rs

src/seeds.rs