build(deps): Bump 8398a7/action-slack from 3.8.3 to 3.9.1

Bumps [8398a7/action-slack](https://github.com/8398a7/action-slack) from 3.8.3 to 3.9.1.
- [Release notes](https://github.com/8398a7/action-slack/releases)
- [Commits](8398a7/action-slack@fac0d8d...dcc8c8e)

Signed-off-by: dependabot[bot] <support@github.com>

.github/workflows/ci.yml

@@ -36,7 +36,7 @@ jobs:
         name: Report code coverage
         with:
           github-token: ${{ secrets.GITHUB_TOKEN }}
-      - uses: 8398a7/action-slack@fac0d8dcd9eec18c79dae8addc99aab092c4cc50
+      - uses: 8398a7/action-slack@dcc8c8e9dd8802e21a712dc0c003db97b42efe43
         name: Notify on Slack
         if: always() # Pick up events even if the job fails or is canceled.
         with: