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 side view thereof; and,
FIG. 3 is a rear perspective view thereof.
The broken lines immediately adjacent to the shaded area represent unclaimed boundaries of the design. The unshaded region within the shaded area that is demarcated by broken lines forms no part of the claimed design. The broken lines showing the remainder of the shoe are for environmental purposes only and form no part of the claimed design.