Fix the velocity smoother being stuck when the deadband is too high (ros-navigation#3690)

* Move last_cmd update before deadband

* fix lint

Author: BriceRenaudeau

nav2_velocity_smoother/src/velocity_smoother.cpp

@@ -305,13 +305,14 @@ void VelocitySmoother::smootherTimer()
     current_.linear.y, command_->linear.y, max_accels_[1], max_decels_[1], eta);
   cmd_vel->angular.z = applyConstraints(
     current_.angular.z, command_->angular.z, max_accels_[2], max_decels_[2], eta);
+  last_cmd_ = *cmd_vel;
 
   // Apply deadband restrictions & publish
   cmd_vel->linear.x = fabs(cmd_vel->linear.x) < deadband_velocities_[0] ? 0.0 : cmd_vel->linear.x;
   cmd_vel->linear.y = fabs(cmd_vel->linear.y) < deadband_velocities_[1] ? 0.0 : cmd_vel->linear.y;
   cmd_vel->angular.z = fabs(cmd_vel->angular.z) <
     deadband_velocities_[2] ? 0.0 : cmd_vel->angular.z;
-  last_cmd_ = *cmd_vel;
+
   smoothed_cmd_pub_->publish(std::move(cmd_vel));
 }