Add IntegralArrays.jl to dependencies

[abhro]

The following line

ImageFeatures.jl/src/brisk.jl

Line 83 in 1d2e4e9

int_img = IntegralArray(img)

uses the IntegralArray() type, (from the IntegralArrays.jl package if I understand correctly) but the package is neither imported nor referenced in the dependencies. On its own, if create_descriptor() is called, it raises an UndefVarError, where `IntegralArray` not defined in `ImageFeatures`