added workflow to trigger clas12-system test

Author: maureeungaro

.github/workflows/trigger_clas12_systems_tests.yml

@@ -0,0 +1,44 @@
+name: Trigger clas12-systems tests
+
+run-name: Triggered by successful deploy workflow
+
+# Fires a workflow_dispatch on gemc/clas12-systems' Test workflow whenever the
+# gemc/src Deploy workflow succeeds on a push to main, i.e. after fresh
+# ghcr.io/gemc/src images (which clas12-systems' tests run inside) are published.
+# Requires a repository secret named CLAS12_SYSTEMS_PAT holding a GitHub Personal
+# Access Token with the `workflow` scope granted on the gemc/clas12-systems repo
+# (mirrors pygemc's GEMC_SRC_PAT, pointing the other way).
+
+permissions:
+  contents: read
+
+concurrency:
+  group: gemc-trigger-clas12-systems-${{ github.event.workflow_run.id }}
+  cancel-in-progress: true
+
+on:
+  workflow_run:
+    workflows: [ "Deploy" ]
+    types: [ completed ]
+
+jobs:
+  dispatch:
+    name: Dispatch clas12-systems Test
+    # Security: only dispatch for a successful push to the base repo. workflow_run
+    # runs privileged (here it consumes CLAS12_SYSTEMS_PAT), so guard against
+    # fork-PR events the same way deploy.yml and binary_tarballs.yml do.
+    if: >-
+      ${{
+        github.event.workflow_run.conclusion == 'success' &&
+        github.event.workflow_run.event == 'push'
+      }}
+    runs-on: ubuntu-latest
+    steps:
+      - name: Trigger workflow_dispatch on gemc/clas12-systems
+        run: |
+          curl --fail-with-body -X POST \
+            -H "Accept: application/vnd.github+json" \
+            -H "Authorization: Bearer ${{ secrets.CLAS12_SYSTEMS_PAT }}" \
+            -H "X-GitHub-Api-Version: 2022-11-28" \
+            https://api.github.com/repos/gemc/clas12-systems/actions/workflows/test.yml/dispatches \
+            -d '{"ref":"main","inputs":{"triggered_by":"gemc/src deploy"}}'