The ornamental design for a luminaire, as shown and described.
FIG. 1 is a perspective view of the luminaire;
FIG. 2 is a left side view thereof;
FIG. 3 is a right side view thereof;
FIG. 4 is a rear view thereof;
FIG. 5 is a front view thereof;
FIG. 6 is a top view thereof; and,
FIG. 7 is a bottom view thereof.
In the drawings, the portions shown by broken lines form no part of the claimed design. Further, a pair of breaks is shown along the extent of a body of the luminaire—namely, a first break residing between a base and a handle of the luminaire, and a second break residing between the handle and a light head of the luminaire. Each break is represented by two undulating broken lines, and the appearance of any portion of the luminaire between the undulating broken lines forms no part of the claimed design.