update CHANGELOG.md

CHANGELOG.md

@@ -5,7 +5,24 @@ All notable changes to `libcasm-monte` 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).
 
-## [v2.0a1] - 2024-03-15
+
+## [2.0a2] - 2024-07-16
+
+### Added
+
+- Added to_json for CompletionCheckParams, SamplingFixtureParams, SamplingParams, jsonResultsIO
+- Added "json_quantities" option to SamplingParams
+- Added Conversions::species_list()
+
+### Changed
+
+- Use shared_ptr to hold sampling fixtures in RunManager
+- Output scalar quantities under "value" key in JSON results output
+- Allow MethodLog to output to stdout
+- Allow constructing libcasm.monte.ValueMap from dict 
+
+
+## [2.0a1] - 2024-03-15
 
 The libcasm-monte package provides useful building blocks for Monte Carlo simulations. This includes: