The ornamental design for a licenseplatesecuritycover, as shown and described.
FIG. 1 is a perspective view of a license plate security cover;
FIG. 2 is a front view thereof;
FIG. 3 is a back view thereof;
FIG. 4 is a side view thereof (opposite side is a mirror image of this view); and,
FIG. 5 is top view thereof (bottom view is a mirror image of this view).
In FIG. 1 and 2, the broken lines showing of environmental structure for purposes of illustrating the license plate security cover device in a condition of use. The broken lines and the structure they depict form no part of the claimed design.