We claim the ornamental design for an upper body garment, as shown and described.
FIG. 1 is a perspective view of an upper body garment showing our new design;
FIG. 2 is a front view thereof.
FIG. 3 is rear view thereof.
FIG. 4 is a right-side view thereof.
FIG. 5 is a left-side view thereof.
FIG. 6 is a top view thereof.
FIG. 7 is a bottom view thereof; and,
FIG. 8 is a perspective view thereof in use.
The broken lines showing elements of the upper body garment in the above-described figures form no part of the claimed design and either illustrate environmental subject matter intended to assist in showing our new design in use or are for illustrative purposes only.