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 lateral view thereof;
FIG. 3 is a medial view thereof;
FIG. 4 is a front view thereof; and,
FIG. 5 is a top view thereof.
The broken lines immediately adjacent to the shaded area define the bounds of the claimed design and form no part thereof. The broken line representing the edge of a toe counter forms no part of the claimed design. The broken lines showing the remainder of the shoe represents unclaimed subject matter and forms no part of the claimed design.