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 second rear perspective view thereof;
FIG. 3 is side view thereof; and,
FIG. 4 is an opposite side view thereof.
The broken lines immediately adjacent to the shaded 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.