I wanted to create a `cumsum`

of tracked values. How do I do that?

I tried the below which failed

```
W = param(rand(12,1))
cumsum(Tracker.data(W), dims = 1) # works
cumsum(W, dims = 1) # this fails
```

I got it to work using matrix multiplication but that’s not ideal as it’s more cumbersome

```
mw = Matrix{Float64}(undef, 12, 12)
mw .= 1
for i = 1:12
for j = i+1:12
mw[i,j]=0
end
end
mw
mw*W # this works
```