ci: notify on failures again

Author: kenranunderscore

.github/workflows/clojure.yml

@@ -19,3 +19,16 @@ jobs:
     - uses: actions/checkout@v4
     - uses: DeterminateSystems/nix-installer-action@main
     - run: nix develop -c lein codox
+
+  notify-test-failures:
+    runs-on: ubuntu-latest
+    needs: [test, codox]
+    if: failure()
+    steps:
+      - env:
+          SECRET: ${{ secrets.MATTERMOST_WEBHOOK_URL }}
+          CHANNEL: "active-clojure"
+          USERNAME: "GitHub"
+        run: |
+          URL=https://github.com/${GITHUB_REPOSITORY}/commit/${GITHUB_SHA}
+          curl -i --data-urlencode "payload={\"channel\":\"${CHANNEL}\", \"username\":\"${USERNAME}\",\"text\":\"Failure in tests: ${URL}\"}" ${SECRET}