[ci] update version.json when new tag pushed

.github/workflows/build.yml

@@ -385,3 +385,20 @@ jobs:
           remote_host: ${{ secrets.SERVER_HOST }}
           remote_user: ${{ secrets.SERVER_USER }}
           remote_key: ${{ secrets.SERVER_KEY }}
+
+      - name: Generate version.json
+        run: |
+          echo "{" > version.json
+          echo "  \"latest_version\": \"${{ steps.version.outputs.VERSION_NUM }}\"" >> version.json
+          echo "}" >> version.json
+          cat version.json
+
+      - name: Upload version.json to server
+        uses: burnett01/rsync-deployments@5.2
+        with:
+          switches: -avzr --delete
+          path: version.json
+          remote_path: /var/www/html/version/
+          remote_host: ${{ secrets.SERVER_HOST }}
+          remote_user: ${{ secrets.SERVER_USER }}
+          remote_key: ${{ secrets.SERVER_KEY }}