The ornamental design for a footwear upper, as shown and described.
FIG. 1 is a perspective view of a footwear upper embodying the new design.
FIG. 2 is a right side view thereof.
FIG. 3 is a front view thereof.
FIG. 4 is a rear view thereof.
FIG. 5 is a top plan view thereof; and,
FIG. 6 is a bottom view thereof.
FIGS. 1–6 show features of an article of footwear in phantom lines. These features are shown for environmental purposes and do not form any part of the claimed design. Further, the phantom lines immediately adjacent the solid-line portions of the design form the boundary of the design, with the phantom lines forming no part of the claimed design.