Trigger robottelo imgae update workflow on merge (#961)

(cherry picked from commit e664f39)

.github/workflows/trigger_robottelo_workflow.yml

@@ -0,0 +1,20 @@
+name: Send trigger for updating robottelo image on quay.
+on:
+  push:
+    branches:
+      - master
+      - 6.*.z
+
+jobs:
+  trigger-robottelo-workflow:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Trigger workflow in robottelo repo
+        run: |
+          curl -L \
+            -X POST \
+            -H "Accept: application/vnd.github+json" \
+            -H "Authorization: Bearer ${{ secrets.CHERRYPICK_PAT }}" \
+            -H "X-GitHub-Api-Version: 2022-11-28" \
+            https://api.github.com/repos/SatelliteQE/robottelo/actions/workflows/update_robottelo_image.yml/dispatches \
+            -d '{"ref":"'"${GITHUB_REF##*/}"'"}'