docs(CHANGES) note libvcs 0.41.0 bump

why: Document the libvcs minimum-version bump in v1.60.x's
unreleased section, matching the convention from v1.59.0 / PR #544
of filing libvcs version bumps under ### Breaking changes as a
single terse bullet (no rationale prose, no Development entry).
what:
- Add ### Breaking changes entry: libvcs 0.40.0 -> 0.41.0

Author: tony

CHANGES

@@ -37,6 +37,10 @@ $ uvx --from 'vcspull' --prerelease allow vcspull
 _Notes on upcoming releases will be added here_
 <!-- END PLACEHOLDER - ADD NEW CHANGELOG ENTRIES BELOW THIS LINE -->
 
+### Breaking changes
+
+- Bump minimum libvcs from 0.40.0 to 0.41.0 (#548)
+
 ### Documentation
 
 - Bump gp-sphinx docs stack to v0.0.1a16 — docs site now renders