chore(deps): bump rtCamp/action-slack-notify from 2.1.2 to 2.1.3

Bumps [rtCamp/action-slack-notify](https://github.com/rtCamp/action-slack-notify) from 2.1.2 to 2.1.3.
- [Release notes](https://github.com/rtCamp/action-slack-notify/releases)
- [Commits](rtCamp/action-slack-notify@v2.1.2...v2.1.3)

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

.github/workflows/build.yml

@@ -50,7 +50,7 @@ jobs:
           verbose: true
       - name: Slack notification when master build fails
         if: ${{ failure() && github.ref == 'refs/heads/master'}}
-        uses: rtCamp/action-slack-notify@v2.1.2
+        uses: rtCamp/action-slack-notify@v2.1.3
         env:
           SLACK_WEBHOOK: ${{ secrets.SLACK_WEBHOOK }}
           SLACK_CHANNEL: cerberus-alerts