The ornamental design for a strollerstrap, as shown and described.
FIG. 1 is a perspective view of a stroller strap illustrating its use relative to a stroller and a shopping basket.
FIG. 2 is a side elevation view thereof, shown broken in the center for ease of illustration;
FIG. 3 is a front view thereof, shown broken in the center for ease of illustration;
FIG. 4 is a rear view thereof, shown broken in the center for ease of illustration; and,
FIG. 5 is a right side view of the stroller strap seen in FIG. 2.
The dashed lines forming the outline of a stroller and a basket seen in FIG. 1 are for environmental purposes only and form no part of the claimed design.