Update changelog

Fix nix build, cli tests with assert_cmd, version bump

Bump minor version

Improve stdin handling, clean up help docs

Update dependencies, simplify parsing

Flakify

Update version number

Update usage string and add description for case conversion

Add links to convert-case

Create License File

Add install instructions, update to v0.4.0

Format, clippy, add test

Final updates to README

Add use cases

Update readme with case conversion description