FIG. 1 is a perspective view of the ornamental design for a pet house;

FIG. 2 is a top plan view thereof;

FIG. 3 is a front elevational view thereof;

FIG. 4 is a right side elevational view thereof, the left side being a mirror image thereof;

FIG. 5 is a rear elevational view thereof; and,

FIG. 6 is a bottom view thereof.