Broadcast product of a `Gain` with a range loses `Gain` units

Hi,

Multiplying a range by a `Gain` loses the `Gain` units:
```julia
(5u"dB"/u"cm") .* (1:10)
# (5:5:50) cm^-1
```

Works fine with normal arrays:
```julia
(5u"dB"/u"cm") .* collect(1:10)
# 10-element Vector{Quantity{Gain{Unitful.LogInfo{:Decibel, 10, 10}, :?, Int64}, 𝐋^-1, Unitful.FreeUnits{(cm^-1,), 𝐋^-1, nothing}}}:
# [5 dB] cm^-1
# [10 dB] cm^-1
# [15 dB] cm^-1
# [20 dB] cm^-1
# [25 dB] cm^-1
# [30 dB] cm^-1
# [35 dB] cm^-1
# [40 dB] cm^-1
# [45 dB] cm^-1
# [50 dB] cm^-1
```

Thanks