I claim the ornamental design for a pet harness, as shown and described.
FIG. 1 is a perspective view of a pet harness, showing a first embodiment of my new design in a fitted configuration;
FIG. 2 is a perspective view of the design of FIG. 1, illustrated in a flat configuration;
FIG. 3 is a left-side elevational view of the design of FIG. 2;
FIG. 4 is a right-side elevational view of the design of FIG. 2;
FIG. 5 is a front elevational view of the design of FIG. 2;
FIG. 6 is a rear elevational view of the design of FIG. 2;
FIG. 7 is a top plan view of the design of FIG. 2; and,
FIG. 8 is a bottom plan view of the design of FIG. 2.
The broken lines showing a pet in FIG. 1 depict environmental matter and form no part of the claimed design. The broken lines on the pet harness depict stitching that forms part of the claimed design.