I claim the ornamental design for a pet shirt with a short cross-over sleeve, as shown and described.
FIG. 1 is a reduced side perspective view of a pet shirt with a short cross-over sleeve according to my new design, the opposite side perspective view being a mirror image thereof;
FIG. 2 is a bottom view thereof; and,
FIG. 3 is a top view thereof.
The broken line showing of a dog in FIG. 1 is for illustrative purposes only and forms no part of the claimed design. The dashed line in FIG. 2 represents stitching and is part of the claimed design.