The ornamental design for a smartplug, as shown and described.
FIG. 1 is a perspective view of a smart plug showing my new design;
FIG. 2 is a front elevational view thereof;
FIG. 3 is a rear elevational view thereof;
FIG. 4 is a left side elevational view thereof;
FIG. 5 is a right side elevational view thereof;
FIG. 6 is a top plan view thereof;
FIG. 7 is a bottom plan view thereof; and,
FIG. 8 is another perspective view thereof shown with a left-side receptacle of the smart plug rotated ninety degrees in one direction and a right-side receptacle of the smart plug rotated ninety degrees in another direction.
The broken lines in the drawings depict portions of the smart plug that form no part of the claimed design.