Version 0.2.19: Soundness hotfix

This version fixes an unsoundness issue (that would unlikely to be a real security issue but may be in the future).

Crates.io: https://crates.io/crates/ffuzzy/0.2.19
Docs.rs: https://docs.rs/ffuzzy/0.2.19/ssdeep/

Full Changelog: v0.2.18...v0.2.19