The ornamental design for a cantilever shelving, as shown and described.
FIG. 1 is a perspective view of the cantilever shelving;
FIG. 2 is a top view thereof;
FIG. 3 is a bottom view thereof;
FIG. 4 is a right side view thereof, the left side view being a mirror image thereof;
FIG. 5 is a front view thereof;
FIG. 6 is a rear view thereof; and,
FIG. 7 is a perspective view of the cantilever shelving in an alternative configuration for storage thereof.
FIGS. 1-7 show features in broken lines. These features do not form any part of the claimed design. Further, any broken lines immediately adjacent the solid-line portions of the design form the boundary of the design, with the broken lines forming no part of the claimed design. The use of separations and brackets indicates that no particular length or width of the cantilever shelving is claimed.