Remove unnecessary workflow_call trigger from actionci caller workflow (#108)

Author: tashian

.github/workflows/actionci.yml

@@ -7,7 +7,6 @@ on:
     branches:
     - "master"
   pull_request:
-  workflow_call:
 
 concurrency:
   group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}