I am using Differential Equations and Unitful together for the first time and I am running into the following error when trying to solve my OdeProblem: `ArgumentError: zero(Unitful.Quantity{Float64}) not defined.`

My ODE is pretty simple and everything has units:

```
function rocket!(du, u, p, t)
ρ = ρ_altitude(u[1]) # kg/m^3
drag = Fd(u[2], ρ) # N
F = thrust - drag # N
du[1] = u[2] # x' = ẋ
du[2] = F / 300000 # ẍ = (thrust - drag) / mass
end
```

The problem works great when I remove the units, I have confirmed that all of the units are valid, and all packages are fully up to date so I am not sure why the argument error is popping up.

If there is any more information needed let me know and I will add it to the post, but the full code is in a comment below: Error using Differential Equations and Unitful - #3 by MisterBiggs