fix(flutter): satisfy curly_braces_in_flow_control_structures lint

flutter_client/lib/update/client_update_provider.dart

@@ -72,8 +72,12 @@ bool isVersionNewer(String serverVersion, String installedVersion) {
   final svr = parts(serverVersion);
   final ins = parts(installedVersion);
   final n = svr.length > ins.length ? svr.length : ins.length;
-  while (svr.length < n) svr.add(0);
-  while (ins.length < n) ins.add(0);
+  while (svr.length < n) {
+    svr.add(0);
+  }
+  while (ins.length < n) {
+    ins.add(0);
+  }
   for (var i = 0; i < n; i++) {
     if (svr[i] > ins[i]) return true;
     if (svr[i] < ins[i]) return false;