The ornamental design for a luminaire, as shown and described.
FIG. 1 is a bottom perspective view of a luminaire showing the new design.
FIG. 2 is a left side elevation view of the luminaire of FIG. 1.
FIG. 3 is a right side elevation view of the luminaire of FIG. 1.
FIG. 4 is a top perspective view of the luminaire of FIG. 1.
FIG. 5 is a front elevation view of the luminaire of FIG. 1.
FIG. 6 is a back elevation view of the luminaire of FIG. 1.
FIG. 7 is a top plan view of the luminaire of FIG. 1; and,
FIG. 8 is a bottom plan view of the luminaire of FIG. 1.
Portions or features of the luminaire not shown in the drawings form no part of the claimed design. The broken lines in the drawings form no part of the claimed design.