Update changelog

CHANGELOG.md

@@ -4,6 +4,18 @@ This file contains notable changes (e.g. breaking changes, major changes, etc.)
 
 This file was introduced starting Kani 0.23.0, so it only contains changes from version 0.23.0 onwards.
 
+## [0.39.0]
+
+## What's Changed
+
+* Limit --exclude to workspace packages by @tautschnig in https://github.com/model-checking/kani/pull/2808
+* Fix panic warning and add arbitrary Duration by @celinval in https://github.com/model-checking/kani/pull/2820
+* Update CBMC version to 5.94 by @celinval in https://github.com/model-checking/kani/pull/2821
+* Rust toolchain upgraded to `nightly-2023-10-16` by @celinval @tautschnig 
+
+**Full Changelog**:
+https://github.com/model-checking/kani/compare/kani-0.38.0...kani-0.39.0
+
 ## [0.38.0]
 
 ### Major Changes