The ornamental design for a shoe upper, as shown and described.
FIG. 1 is side view of a shoe upper showing my new design;
FIG. 2 is a rear view thereof; and,
FIG. 3 is a second side view thereof.
The broken line immediately adjacent to the bottom of the shaded area defines the bounds of the claimed design and forms no part thereof. The broken lines showing the remainder of the shoe are for environmental purposes only and form no part of the claimed design.