adding new job notify-slack (Xilinx#8019)

* adding new job notify-slack on failure

* notify slack depends only on gradle-artifactory-upload job

* notify slack depends on release to all sites and gradle artifactory upload

.github/workflows/xrt_master.yml

@@ -591,5 +591,16 @@ jobs:
           github-server-url: ${{ secrets.SERVER_URL }}
           sshKey: ${{ secrets.CI_PRIVATE_SSH_KEY }}
           runnerName: ${{ runner.name }}
-
 
+  notify-slack:  
+    needs: [Release_to_all_sites, gradle-artifactory-upload]  
+    runs-on: Ubuntu-22.04
+    if: always() && contains(needs.*.result, 'failure')  
+    steps:  
+      - name: Notify Slack on failure  
+        uses: 8398a7/action-slack@v3  
+        with:  
+          status: ${{ job.status }}  
+          fields: repo,message,commit,author,action   
+        env:  
+          SLACK_WEBHOOK_URL: ${{ secrets.SLACK_WEBHOOK_URL }}