Incorrect array size validation for vec3 in Python bindings

[markdjwilliams]

I believe there's a typo in the Python bindings which impacts writing vec3 attributes into OpenEXR headers from numpy arrays.

openexr/src/wrappers/python/PyOpenEXR.cpp

Line 1557 in 39010bf

if (a.ndim() == 1 && a.size() == 2)

    else if (py::isinstance<py::array_t<T>>(object))
    {
        auto a = object.cast<py::array_t<T>>();
        if (a.ndim() == 1 && a.size() == 2)
        {
            auto p = static_cast<T*>(a.request().ptr);
            v.x = p[0];
            v.y = p[1];
            v.z = p[2];
            return true;
        }
    }

The 2 should be a 3 for it to correctly detect arrays of the correct size.

[cary-ilm]

Thanks for the catch, yes, apparently a copy/paste error from objectToV2. And unfortunately the bug was specific to float but the test only validated double. Should be fixed in #1945.