The ornamental design for a luminaire, as shown and described.
FIG. 1 is a top isometric view of an ornamental design for a luminaire;
FIG. 2 is a bottom isometric view of the luminaire of FIG. 1;
FIG. 3 is a top plan view of the luminaire of FIG. 1;
FIG. 4 is a right side elevational view of the luminaire of FIG. 1;
FIG. 5 is a front elevational view of the luminaire of FIG. 1;
FIG. 6 is a back elevational view of the luminaire of FIG. 1;
FIG. 7 is a left side elevational view of the luminaire of FIG. 1; and,
FIG. 8 is a bottom plan view of the luminaire of FIG. 1.
The broken lines (where present) in all FIGS. illustrate portions of the luminaire that form no part of the claimed design. The dash-dot lines (where present) are for the purpose of defining the bounds of the claimed design and form no part of the claimed design.