add a changelog

CHANGELOG.md

@@ -0,0 +1,17 @@
+# Changelog
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## [Unreleased](https://github.com/cryptomator/siv-mode/compare/1.5.2...HEAD)
+
+### Added
+
+- This CHANGELOG file
+- `encrypt(SecretKey key, byte[] plaintext, byte[]... associatedData)` and `decrypt(SecretKey key, byte[] ciphertext, byte[]... associatedData)` using a single 256, 384, or 512 bit key
+
+### Changed
+
+- use `maven-gpg-plugin`'s bc-based signer