Add changelog entry.

Author: peter-hofer

substratevm/CHANGELOG.md

@@ -7,6 +7,7 @@ This changelog summarizes major changes to GraalVM Native Image.
 * (GR-39390) (GR-39649) (GR-40033) Red Hat added support for the JFR events `JavaMonitorEnter`, `JavaMonitorWait`, and `ThreadSleep`.
 * (GR-39497) Add `-H:BuildOutputJSONFile=<file.json>` option for [JSON build output](https://github.com/oracle/graal/edit/master/docs/reference-manual/native-image/BuildOutput.md#machine-readable-build-output). Please feel free to provide feedback so that we can stabilize the schema/API.
 * (GR-40170) Add `--silent` option to silence the build output.
+* (GR-39563) Add support for JDK 19 and Project Loom Virtual Threads (JEP 425) for high-throughput lightweight concurrency. Enable on JDK 19 with `native-image -J--enable-preview`.
 
 ## Version 22.2.0
 * (GR-20653) Re-enable the usage of all CPU features for JIT compilation on AMD64.