The ornamental design for a shoe upper, as shown and described.
FIG. 1 is a front-right side perspective view of a shoe upper;
FIG. 2 is a front view thereof;
FIG. 3 is a rear view thereof;
FIG. 4 is a left side view thereof;
FIG. 5 is a right side view thereof;
FIG. 6 is a top view thereof; and,
FIG. 7 is a bottom view thereof.
The broken lines showing in the figures are included for the purpose of illustrating the environment in which the design is used and form no part of the claimed design.