The ornamental design for a cheeseboard, as shown and described.
FIG. 1 is a perspective view of a using state of a cheese board showing my new design;
FIG. 2 is a perspective view thereof;
FIG. 3 is a perspective view of folded state thereof;
FIG. 4 is a top plan view thereof;
FIG. 5 is a front view thereof;
FIG. 6 is a back side view thereof;
FIG. 7 is a right side view thereof;
FIG. 8 is a left side view thereof; and,
FIG. 9 is a bottom plan view thereof.
The dashed or broken lines shown in the drawings depict portions of the cheese board in which the design is embodied that form no part of the claimed design.