The ornamental design for a portion of a shoe upper, as shown and described.
FIG. 1 is a first perspective view of a portion of a shoe upper showing my new design;
FIG. 2 is a side view thereof; and,
FIG. 3 is a second perspective view thereof.
The uneven broken line immediately adjacent to the shaded area represents an unclaimed boundary of the design. The uneven broken line showing of three tear-shaped disclaimed regions within the shaded area of FIGS. 1-3 is for illustrative purposes only and forms no part of the claimed design. The uneven broken line showing of the remainder of the shoe is for illustrative purposes only and forms no part of the claimed design.