riscv: update changelog

Author: hegza

riscv/CHANGELOG.md

@@ -7,6 +7,11 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 ## [Unreleased]
 
+### Added
+
+- CSR helper macro `write_composite_csr` for writing 64-bit CSRs on 32-bit targets.
+- Write utilities for `mcycle`, `minstret`
+
 ## [v0.13.0] - 2025-02-18
 
 ### Added