chore(release): regenerate api/openapi.json for 0.4.2

The OpenAPI info.version tracks the crate version, so the 0.4.2 bump
(0604c4f) left api/openapi.json stale at 0.4.1 and would redden
mgmt::tests::openapi_document_is_complete_and_checked_in. The API surface is
unchanged since the last regen (ecbbff5 already refreshed it for the new
library endpoints), so this is the version string only.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

api/openapi.json

@@ -10,7 +10,7 @@
       "name": "MIT OR Apache-2.0",
       "identifier": "MIT OR Apache-2.0"
     },
-    "version": "0.4.1"
+    "version": "0.4.2"
   },
   "paths": {
     "/api/v1/clients": {