multistep.prediction: Multi step prediction with updated dynamics
In vcerqueira/vest: automatic feature eng for forecasting

Multi step prediction with updated dynamics

1 2	multistep.prediction(model, x, dyns, h, ft_model, update.dynamics = TRUE, model_cols, predfun)

`model`	Predictive model
`x`	Past lags in the test data
`dyns`	Dynamics in the test data (for h=1)
`h`	Forecasting horizon
`ft_model`	Feat engineer model for updating dynamics
`update.dynamics`	logical. If true, dynamics are updated for h>1
`model_cols`	Names of the features in trained model
`predfun`	Prediction fun for making predictions using model