Update slack notify version to 2.2.1 (#8)

Author: HofmT

.github/workflows/release-deploy-docker.yml

@@ -47,7 +47,7 @@ jobs:
           args: push ${GITHUB_REPOSITORY}:${{ steps.ownEnvVars.outputs.PACKAGE_VERSION }}
 
       - name: Slack Notification - Release
-        uses: rtCamp/action-slack-notify@v2.0.0
+        uses: rtCamp/action-slack-notify@v2.2.1
         env:
           SLACK_WEBHOOK: ${{ secrets.SLACK_WEBHOOK }}
           SLACK_USERNAME: "dockerBot"