output DockerHub digest in publish-docker-next workflow (#9471)

.github/workflows/publish-docker-next.yml

@@ -29,6 +29,7 @@ jobs:
         run: echo "SHORT_SHA=${GITHUB_SHA::7}" >> $GITHUB_ENV
 
       - name: Build and push to DockerHub
+        id: docker_build_push
         uses: docker/build-push-action@v4
         with:
           context: .
@@ -37,6 +38,9 @@ jobs:
           build-args: |
             version=${{ env.SHORT_SHA }}
 
+      - name: Output Image Digest
+        run: echo ${{ steps.docker_build_push.outputs.digest }} >> $GITHUB_STEP_SUMMARY
+
       - name: Login to GHCR
         uses: docker/login-action@v2
         with: