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;
FIG. 3 is a rear perspective view thereof;
FIG. 4 is a top view thereof; and,
FIG. 5 is a second side view thereof.
The unshaded regions in the interior of the eyelets form no part of the claimed design. The broken lines showing the remainder of the shoe represent unclaimed subject matter and form no part of the claimed design.