We claim the ornamental design for a headwear towel, as shown and described.
FIG. 1 is a perspective view of a headwear towel, shown in use by a user, incorporating our new design;
FIG. 2 is a front elevation view thereof;
FIG. 3 is a rear elevation view thereof;
FIG. 4 is a left side elevation view thereof;
FIG. 5 is a right side elevation view thereof;
FIG. 6 is a top plan view thereof; and,
FIG. 7 is a bottom plan view thereof.
The broken lines showing a person in FIG. 1 are included for the purpose of illustrating the headwear towel in use by a user, and form no part of the claimed design. The broken lines along the towel back depict claimed stitching.