The ornamental design for a petboot, as shown and described.
FIG. 1 is a top, front perspective view of a pet boot, shown in a first configuration for use with the boot strap closed and shown enlarged for clarity of disclosure;
FIG. 2 is a top, front perspective view of the pet boot of FIG. 1 shown in a second configuration for use with the boot strap open and shown at a reduced scale;
FIG. 3 is a right elevation view of the pet boot of FIG. 1, shown in the first configuration for use;
FIG. 4 is a right elevation view of the pet boot of FIG. 1, shown in the second configuration for use;
FIG. 5 is a top, plan view of the pet boot of FIG. 1, shown in the first configuration for use; and,
FIG. 6 is a front elevation view of the pet boot of FIG. 1, shown in a third configuration for use without the boot strap.