We claim the ornamental design for a portable shelter, as shown and described.
FIG. 1 is a perspective view of a portable shelter being worn by a user in a closed configuration and showing a top, a front and a right side.
FIG. 2 is a rear elevational view of the portable shelter.
FIG. 3 is a top plan view of the portable shelter in an opened configuration and showing a top, a front, a rear and left and right sides.
FIG. 4. is a right side elevational view of the portable shelter in the opened configuration of FIG. 3.
FIG. 5 is a left side elevational view of the portable shelter in the opened configuration of FIG. 3.
FIG. 6 is a bottom plan view of the portable shelter in the opened configuration and showing a bottom and inner surfaces of the front, the rear and the right and left sides.
FIG. 7. is a right side elevational view of the portable shelter in the opened configuration of FIG. 6; and,
FIG. 8 is a left side elevational view of the portable shelter in the opened configuration of FIG. 6.
The broken line showings of the internal pocket, the head opening and the side zippers illustrate portions of the portable shelter that form no part of the claimed design. The broken line showing of a portion of the user illustrates the environment of the claimed design and forms no part thereof.