dynamicHMC UndefVarError

Hi,

I am trying to recreate the simple example in `2019-oct-demo.jl` but it seems that `dynamicHMC` function is not recognized! Was the function changed or am I missing something? This is the error stacktrace:
```
ERROR: UndefVarError: dynamicHMC not defined
Stacktrace:
 [1] getproperty(x::Module, f::Symbol)
   @ Base ./Base.jl:35
 [2] top-level scope
   @ REPL[177]:1
```

Thanks.