The ornamental design for a swing, as shown and described.
FIG. 1 is a front perspective view of a swing according to the present invention.
FIG. 2 is a side elevation view of the swing illustrated in FIG. 1.
FIG. 3 is another side elevation view of the swing illustrated in FIG. 1.
FIG. 4 is another side elevation view of the swing illustrated in FIG. 1.
FIG. 5 is another side elevation view of the swing illustrated in FIG. 1.
FIG. 6 is a top plan view of the swing illustrated in FIG. 1; and,
FIG. 7 is a bottom plan view of the swing illustrated in FIG. 1.
The broken lines showing strings, hooks, and a child are for the purpose of illustrating environmental structure and form no part of the claimed design.