Update changelog

Author: sgued

CHANGELOG.md

@@ -7,7 +7,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 ## [Unreleased]
 
-- Fixed unsoundness in `Deque::clear`, `HistoryBuf::clear` and `IndexMap::clear` in the context
+- Fixed unsoundness in `Deque::clear`, `HistoryBuf::clear`, `IndexMap::clear`, `Vec::IntoIter::drop` and `HistoryBuf::write` in the context
 of panicking drop implementations.
 - Added `from_bytes_truncating_at_nul` to `CString`
 - Added `CString::{into_bytes, into_bytes_with_nul, into_string}`