omriKramer

[AutoARIMA] when using AutoARIMA on a constant time series the forecast fitted values are zero no matter the constant.

1

### What happened + What you expected to happen When fitting AutoARIMA to a constant series the forecast fitted values will be zeros even though the out of sample forecast...

fix: Mh update in _class3models

3

`Mh` was outside the loop looping over `h`, therefore it didn't update and all variance terms were scaled by the first prediction.