Inconsistency between accepted argument types for YCbCr constructor and colorview

[yakir12]

There seem to be some inconsistencies in the accepted argument-types to the YCbCr constructor and the element-types of the channels in colorview.

Here, all the following types work:

using ImageCore
types = (UInt8, Int, N0f8, Float32)

for T in types
    YCbCr(rand(T, 3)...)
end

While here, only the Float32 does:

for T in types
    try
        colorview(YCbCr, (rand(T, 10, 10) for _ in 1:3)...)
        @info "worked for type $T"
    catch ex
        if ex isa TypeError
            @warn "failed for type $T"
        else
            throw(ex)
        end
    end
end