update CHANGELOG

CHANGELOG.md

@@ -38,7 +38,10 @@ and follow [semantic versioning](https://semver.org/) for our releases.
 - [#144](https://github.com/EspressoSystems/jellyfish/pull/144) (`jf-primitives`) Updated append-only merkle tree gadget with the latest MT API
 - [#119](https://github.com/EspressoSystems/jellyfish/pull/119) (all) Updated dependencies
   - Upgraded `criterion` from `0.3.1` to `0.4.0`
-
+- [#148](https://github.com/EspressoSystems/jellyfish/pull/148), [#156](https://github.com/EspressoSystems/jellyfish/pull/156) (`jf-primitives`) Refactored BLS Signature implementation
+  - #148 Added trait bounds on associated types of `trait SignatureScheme`
+  - #156 Improved BLS correctness and API compliance with IRTF standard with better doc
+
 ### Fixed
 
 - [#76](https://github.com/EspressoSystems/jellyfish/pull/76) (`jf-plonk`) Splitting polynomials are masked to ensure zero-knowledge of Plonk