The ornamental design for a shoe upper, as shown and described.
FIG. 1 is a front perspective view of a shoe upper showing my new design;
FIG. 2 is a side view thereof;
FIG. 3 is a front view thereof; and,
FIG. 4 is a top view thereof.
The photographic area is claimed. The broken lines immediately adjacent to the photographic area represent unclaimed boundaries of the design. The broken lines showing the remainder of the shoe are for environmental purposes only and form no part of the claimed design.