The ornamental design for a petcage, as shown and described.
FIG. 1 is front elevational view of a first embodiment of a pet cage in which a door of the pet cage is shown in a closed position showing, my new design;
FIG. 2 is a left side elevational view thereof; a right side elevational view is a mirror image of the left side elevational view;
FIG. 3 is a top plan view thereof;
FIG. 4 is an isometric view thereof, showing the door of the pet cage in a closed position;
FIG. 5 is an isometric view thereof, showing the door of the pet cage in an open position; and,
FIG. 6 is an isometric view of a second embodiment of the pet cage, in which a door of the pet cage is shown in a closed position, showing my new design. The left and right side elevational views are identical to FIG. 2.
The broken lines in the views depict portions of the pet cage that form no part of the claimed design.