The ornamental design for a swimmingcostume, as shown and described.
FIG. 1 is a front view of a swimming costume showing my new design;
FIG. 2 is a left side view thereof;
FIG. 3 is a rear view thereof;
FIG. 4 is a right side view thereof;
FIG. 5 is a front view of a second embodiment of the swimming costume;
FIG. 6 is a left side view thereof;
FIG. 7 is a rear view thereof; and,
FIG. 8 is a right side view thereof.
The broken line showing of the body of a person and zipper is for illustrative purposes only and forms no part of the claimed design.
The stippling is used to indicate color contrast and is not a feature of the claimed design.
The broken lines other than those representing the body of the person and the zipper are understood to represent striping on the costume surface which forms no part of the claimed design.