Use the alias TimeVaryingDCMPlannerDynamics::StateDerivativeType inst…

…ead of std::tuple<> in TimeVaryingDCMPlanner

src/Planners/src/TimeVaryingDCMPlanner.cpp

@@ -239,7 +239,7 @@ struct TimeVaryingDCMPlanner::Impl
  dcmDynamicalSystem->setState({dcm(Sl(), 0), omega(Sl(), 0)});
  dcmDynamicalSystem->setControlInput({vrp(Sl(), 0), omegaDot(Sl(), 0)});
 
- std::tuple<casadi::MX, casadi::MX> stateDerivative;
+ TimeVaryingDCMPlannerDynamics::StateDerivativeType stateDerivative;
  dcmDynamicalSystem->dynamics(0, stateDerivative);
 
  const auto& [initialDcmVelocity, initialOmegaVelocity] = stateDerivative;