Update stacklok/toolhive-registry-server to v1.4.6 (#914)

* Update stacklok/toolhive-registry-server to v1.4.6

Signed-off-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

* Note no doc changes needed for registry-server v1.4.6

* Add upstream-release-docs content for toolhive-registry-server v1.4.6

---------

Signed-off-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>
Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>
Co-authored-by: claude[bot] <41898282+claude[bot]@users.noreply.github.com>

Author: renovate[bot]

.github/upstream-projects.yaml

@@ -20,7 +20,7 @@
 projects:
   - id: toolhive-registry-server
     repo: stacklok/toolhive-registry-server
-    version: v1.4.5
+    version: v1.4.6
     docs_paths:
       - docs/toolhive/guides-registry
       - docs/toolhive/concepts/registry-criteria.mdx