add dispatch (#5667)

.github/workflows/sandbox.yaml

@@ -776,3 +776,34 @@ jobs:
       - name: Push Docker images
         run: |
           docker push kubeshop/testkube-sandbox:${{ matrix.service }}-${{ env.branch_identifier }}-${{ steps.commit.outputs.short }}
+
+  dispatch:
+    needs:
+      [
+          api,
+          single_executor,
+          executor_jmeter,
+          executor_maven,
+          executor_gradle,
+          executor_cypress,
+          executor_cypress_manifest,
+          executor_playwright,
+          log_server_sidecar,
+          testworkflow
+      ]
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/create-github-app-token@v1
+        id: app-token
+        with:
+          app-id: ${{ secrets.APP_ID }}
+          private-key: ${{ secrets.PRIVATE_KEY }}
+          owner: ${{ github.repository_owner }}
+
+      - name: Repository dispatch
+        uses: peter-evans/repository-dispatch@v2
+        with:
+          token: ${{ steps.app-token.outputs.token }}
+          repository: kubeshop/testkube-deployment
+          event-type: sandbox_image_update
+          client-payload: '{"ref_name": "${{ github.ref_name }}"}'