fix: add workflow_call trigger to ci.yml for publish workflow

The publish.yml workflow calls ci.yml but ci.yml was missing the
workflow_call trigger, causing the release to fail.

This enables ci.yml to be reused by other workflows.

Author: JacobCoffee

.github/workflows/ci.yml

@@ -5,6 +5,7 @@ on:
     branches: [main]
   pull_request:
     branches: [main]
+  workflow_call:
 
 jobs:
   # Test suite with coverage