CHANGELOG: add explicit u32 cast entry

Author: dannywillems

CHANGELOG.md

@@ -187,6 +187,8 @@ and this project adheres to
 - Add strict clippy lints (`clippy::all`, `clippy::pedantic`, `clippy::nursery`,
   `unsafe_code`) and fix all warnings
   ([#3480](https://github.com/o1-labs/proof-systems/pull/3480))
+- Replace `i as u32` cast with `u32::try_from(i).unwrap()` in SRS creation
+  ([#3483](https://github.com/o1-labs/proof-systems/pull/3483))
 
 ### [turshi](./turshi)