fix: correct manifest to last released version

Release-As: 5.0.0-alpha.21.1

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <[email protected]>

Author: dbrattli

.release-please-manifest.json

@@ -1,3 +1,3 @@
 {
-  ".": "5.0.0-alpha.21.1"
+  ".": "5.0.0-alpha.21.0"
 }