Hi Takeshi,
As promised, we’ve just released new plugin version 2.9.0, where I’ve added new alg_wc_crowdfunding_campaign_ended action. Please check the Description for an example.
Not directly related to your request, but I’ve also added option to send an email on campaign ended (“Admin Email: Campaign Ended” option in “WooCommerce > Settings > Crowdfunding > General > Ending Options”).
Please let me know if something is not working as expected.
P.S. If you like the plugin, please consider leaving us a rating.