I claim the ornamental design for footwear, as shown and described.
FIG. 1 is a perspective view of footwear; and,
FIG. 2 is a left side view of footwear as shown in FIG. 1.
The dash-dot-dash lines are included for illustrating environmental structure and form no part of the claimed design. The dashed lines represent stitching which form no part of the claimed design.