The ornamental design for a luggage, as shown and described.
FIG. 1 is a front perspective view of an embodiment of a luggage in an expanded condition;
FIG. 2 is a rear view thereof;
FIG. 3 is a front view thereof;
FIG. 4 is a left side view thereof;
FIG. 5 is a right side view thereof;
FIG. 6 is a top view thereof;
FIG. 7 is a bottom view thereof; and,
FIG. 8 is a front perspective view thereof in a collapsed condition.
The broken lines shown in the figures illustrate structure or features that form no part of the claimed design. The drawings include grey surface shading that represents contour and not surface ornamentation or color. The dot-dash broken lines in the figures show boundaries of the claimed design.