The ornamental design for a vacuumattachment, as shown and described.
FIG. 1 is a lower left perspective view thereof, the broken line disclosure representing a house having gutters mounted thereto being for illustrative purposes only forming no part of the claimed design;
FIG. 2 is a left side elevation view thereof;
FIG. 3 is right side elevation view thereof;
FIG. 4 is a top plan view thereof; and,
FIG. 5 is a bottom plan view thereof.
The broken lines included showing use and environment only forming no part of the claimed design.