build: update find-inactive-collaborators labels

Automatically add `blocked` label for find-inactive-collaborators's PRs.

Refs: nodejs#41154 (comment)

Author: Mesteery

.github/workflows/find-inactive-collaborators.yml

@@ -39,5 +39,5 @@ jobs:
           branch: actions/inactive-collaborators
           body: This PR was generated by tools/find-inactive-collaborators.yml.
           commit-message: "meta: move one or more collaborators to emeritus"
-          labels: meta
+          labels: meta, blocked
           title: "meta: move one or more collaborators to emeritus"