The ornamental design for a container, as shown and described.
FIG. 1 is a top, front, right perspective view of a container showing my new design;
FIG. 2 is a top, front, right perspective view of FIG. 1 in an alternate position;
FIG. 3 is a front view thereof;
FIG. 4 is a rear view thereof;
FIG. 5 is a left side view thereof, wherein the right side is an identical image of FIG. 5; and,
FIG. 6 is a top view thereof.
The broken lines immediately adjacent to the shaded area represent unclaimed boundaries of the design. The broken lines showing the remainder of the container are for environmental purposes only and form no part of the claimed design.