Add python version to slack message title

.github/workflows/unit_tests.yml

@@ -71,7 +71,7 @@ jobs:
         env:
           SLACK_COLOR: ${{ env.SLACK_COLOR }}
           SLACK_WEBHOOK: ${{ secrets.ACTIONS_SLACK_WEBHOOK }}
-          SLACK_TITLE: "Workflow `${{ github.workflow }}`: ${{ job.status }}"
+          SLACK_TITLE: "Workflow `${{ github.workflow }}` (python ${{ matrix.python }}): ${{ job.status }}"
           SLACK_MESSAGE: "Run <https://github.com/${{ github.repository }}/actions/runs/${{ github.run_id }}|#${{ github.run_number }}> on <https://github.com/${{ github.repository }}/|${{ github.repository }}@${{ github.ref }}>"
           SLACK_FOOTER: "<https://github.com/${{ github.repository }}/commit/${{ github.sha }}|View commit>"
           MSG_MINIMAL: true  # use compact slack message format