docs: update changelog for viem dependency removal

Co-authored-by: jeffsmale90 <jeffsmale90@users.noreply.github.com>

Author: cursoragent

packages/x402/CHANGELOG.md

@@ -7,6 +7,14 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Changed
+
+- **BREAKING:** Address normalization now returns lowercase addresses instead of EIP-55 checksummed addresses ([#244](https://github.com/MetaMask/smart-accounts-kit/pull/244))
+
+### Removed
+
+- **BREAKING:** Removed `viem` peer dependency - now using custom Ethereum address and hex validation utilities ([#244](https://github.com/MetaMask/smart-accounts-kit/pull/244))
+
 ## [0.1.0]
 
 ### Added