FIG. 1 is a perspective view of a luminaire, showing our new design;

FIG. 2 is a front elevation view thereof. The right-side elevation view, rear elevation view, and left-side elevation view are identical to the front elevation view;

FIG. 3 is a bottom plan view thereof; and,

FIG. 4 is a top plan view thereof.

The broken lines shown represent unclaimed subject matter and form no part of the claimed design.