Marcgrep

Fix a bug where the leader wouldn't print if you used the `--color` flag. Since output is technically different now I made this a minor rather than patch release.

**Full Changelog**: https://github.com/phette23/marcgreppy/compare/v1.2.0...v1.3.0

New `--invert` flag changes the default color scheme of the `--color` flag for use with a light (e.g. white) terminal background.

**Full Changelog**: https://github.com/phette23/marcgreppy/compare/v1.1.0...v1.2.0

Work with multiple file arguments like `marcgrep OPTIONS file1.mrc file2.mrc`. In shells with glob expansion, you can now do `marcgrep OPTIONS *.mrc`.

**Full Changelog**: https://github.com/phette23/marcgreppy/compare/v1.0.4...v1.1.0

**ci**: `pipx install poetry` instead of depending on another github action

**Full Changelog**: https://github.com/phette23/marcgreppy/compare/v1.0.3...v1.0.4

This release merely adds the "5 - Production/Stable" Development Status on PyPI. I also did the release right so the artifacts attached on GitHub.

**Full Changelog**: https://github.com/phette23/marcgreppy/compare/v1.0.0...v1.0.3

--color` colorized mnemonic MARC output with env var configuration for colors and symbols.

**Full Changelog**: https://github.com/phette23/marcgreppy/compare/v0.4.0...v1.0.0