Changelog for AesonBson-0.4.1

# 0.4.1 * Compatibility with current `aeson` 2.0 (https://github.com/nh2/aesonbson/pull/12) # 0.4.0 * Compatibility with current `aeson` (https://github.com/nh2/aesonbson/pull/11) # 0.2.1 * Fixed BSON ObjIDs being converted incorrectly (https://github.com/nh2/aesonbson/pull/2)