message: add CORS header, set Content-Type: application/json
diff: @@ -47,7 +47,10 @@ def log_init():
  async def health(request):
  - return web.Response()
  + return web.json_response(
  + headers={
  + 'Access-Control-Allow-Origin': '*'
  + })
  # Support for running using aiohttp CLI.
  