I hit this issue too, but there was an easy fix. Just add an Entitlements file to your plugin (in my case the Notification Extension) and give it some dummy capability like Associated Domains. After that it will generate an entitlements file and associate it with the target (you can go to the target's build settings and type code signing to confirm). After adding this file the archive got pushed successfully to ASC
Topic:
Code Signing
SubTopic:
Entitlements
Tags: