Update CHANGELOG for multi-version annotations and CurrentOrOlder filter

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: halspang

CHANGELOG.md

@@ -1,6 +1,7 @@
 # Changelog
 
 ## Unreleased
+- Support declaring multiple versions in a single `[DurableTask]` attribute via a comma-separated list (for example `[DurableTask("MyActivity", Version = "1.0.0,1.1.0")]`); each version is registered and plumbed through code generation. Narrow auto-generated work item filters to current-or-older versions under the `CurrentOrOlder` match strategy.
 
 
 ## v1.25.0-preview.2