Bump 8398a7/action-slack from 3.15.1 to 3.16.2

Bumps [8398a7/action-slack](https://github.com/8398a7/action-slack) from 3.15.1 to 3.16.2.
- [Release notes](https://github.com/8398a7/action-slack/releases)
- [Commits](8398a7/action-slack@fbd6aa5...28ba43a)

---
updated-dependencies:
- dependency-name: 8398a7/action-slack
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

.github/workflows/notifications.yml

@@ -44,7 +44,7 @@ jobs:
             }
 
       - name: Send Notification
-        uses: 8398a7/action-slack@fbd6aa58ba854a740e11a35d0df80cb5d12101d8 # v3.15.1
+        uses: 8398a7/action-slack@28ba43ae48961b90635b50953d216767a6bea486 # v3.16.2
         with:
           status: custom
           custom_payload: |