Add a new daily job to add JiHu contribution label

Part of triage-serverless#105 (closed)

Counterpart for triage-serverless: triage-serverless!107 (merged)

Action items

• (If applicable) Add documentation to the handbook pages for Triage Operations =>
• (If applicable) Identify the affected groups and how to communicate to them:
  • /cc @person_or_group =>
  • Relevant Slack channels =>
  • Week-in-review