Add CHANGELOG entry for fixing #1978

(cherry picked from commit 1b110c6)

CHANGELOG.md

@@ -12,6 +12,13 @@ and this project adheres to
 
 - cosmwasm-vm: Fix CWA-2023-004.
 
+### Fixed
+
+- cosmwasm-vm: Fix memory increase issue (1.3 -> 1.4 regression) by avoiding the
+  use of a long running Wasmer Engine. ([#1978])
+
+[#1978]: https://github.com/CosmWasm/cosmwasm/issues/1978
+
 ### Added
 
 - cosmwasm-vm: Add constructor `CacheOptions::new`