The ornamental design for a shoe upper, as shown and described.
FIG. 1 is a front perspective view of a portion of a shoe upper showing my new design;
FIG. 2 is a front view thereof;
FIG. 3 is a rear view thereof;
FIG. 4 is a medial side view thereof;
FIG. 5 is a lateral side view thereof; and
FIG. 6 is a top view thereof.
The uneven broken lines showing various regions and the remainder of the shoe is for illustrative purposes only and forms no part of the claimed design.