The ornamental design for a shoe upper, as shown and described.
FIG. 1 is a rear perspective view of a shoe upper showing my new design;
FIG. 2 is a side view thereof; and,
FIG. 3 is a front perspective view thereof.
The broken lines immediately adjacent to the shaded area represent unclaimed boundaries of the design. The broken lines showing of the triad-shaped-regions and the remainder of the shoe represent unclaimed subject matter and form no part of the claimed design.