The ornamental design for headwear, as shown and described.
FIG. 1 is a first side view of headwear showing my new design;
FIG. 2 is a rear and first side view in perspective thereof;
FIG. 3 is a second side view thereof;
FIG. 4 is a rear and second side view in perspective thereof;
FIG. 5 is a front view thereof;
FIG. 6 is a rear view thereof;
FIG. 7 is a top view thereof;
FIG. 8 is a front and second side view in perspective thereof; and,
FIG. 9 is a front and first side view in perspective thereof.
The broken line outline of the partial human figure and the bill assist in illustrating how the claimed design may appear when in a position of use, but form no part of the claimed design. The broken lines along the surfaces of the headwear depict features of the article that form no part of the claimed design.