chore: update changelog

Author: Edmo Lima

CHANGELOG.md

@@ -0,0 +1,17 @@
+## [1.0.0] - 2025-07-23
+
+### Added
+- Initial public release of docdiff.
+- Fast and robust document distance algorithm (cosine similarity).
+- CLI with friendly feedback and verdicts (identical, similar, different).
+- Multiplatform support (macOS, Linux, Windows).
+- Automated release workflow with changelog and GitHub Release integration.
+
+### Changed
+- Modular codebase for scalability and maintainability.
+
+### Fixed
+- Lint and formatting issues resolved for Rust 2024 edition.
+
+### Security
+- No known security issues in this release.