rm Slack integration.

for now. let's bring it back when we have a plan for which channel to
report into.

.github/workflows/ci.yml

@@ -5,8 +5,6 @@ on:
   pull_request:
   schedule:
     - cron: '33 2 * * 1' # weekly, on Monday morning
-env:
-  SLACK_WEBHOOK_URL: ${{ secrets.SLACK_ILIOS_DEPLOYMENT_WEBHOOK_URL }}
 
 jobs:
   test:
@@ -119,10 +117,4 @@ jobs:
 
       - name: Mark cancelled jobs as failed.
         if: ${{ cancelled() }}
-        run: exit 1
-
-      - uses: act10ns/[email protected]
-        with:
-          status: ${{ job.status }}
-          message: Moodle Plugin CI failed {{ env.GITHUB_SERVER_URL }}/{{ env.GITHUB_REPOSITORY }}/actions/runs/{{ env.GITHUB_RUN_ID }}
-        if: failure()
+        run: exit 1