Fix release note formatting
This broke the building of the release notes.
MODIFY
releasenotes/notes/add-converge-in-osc-stack-update-10f256589f628d13.yaml
releasenotes/notes/add-converge-in-osc-stack-update-10f256589f628d13.yaml
---
features:
- - Adds '--converge' option for stack update with openstackclient. If
+ - |
+ Adds '--converge' option for stack update with openstackclient. If
specified, existing resource attributes (which may have diverged) are
compared with the resource properties in the template used for update.

Fix release note formatting

This broke the building of the release notes.

Change-Id: I6d9519aaf591e817e71a777a75fdc1d6caa7c17a