Ventilation Cover

FIG. 1 is a first perspective view of a ventilation cover showing my new design; FIG. 2 is a second perspective view thereof; FIG. 3 is a front view thereof; FIG. 4 is a back view thereof; FIG. 5 is a left side view thereof; FIG. 6 is a right side view thereof; FIG. 7 is a top view thereof; FIG. 8 is a bottom view thereof; and, FIG. 9 is a perspective view of another state of the ventilation cover thereof. The broken lines shown in the drawings depict portions of the ventilation cover that form no part of the claimed design.