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 second front perspective view thereof;
FIG. 3 is a top view thereof; and,
FIG. 4 is an enlarged view of FIG. 3 with unclaimed subject matter omitted.
The broken lines immediately adjacent to the photographic area represent unclaimed boundaries of the design. The broken lines showing the remainder of the shoe represent unclaimed subject matter and form no part of the claimed design.