The ornamental design for a cartridge for a beveragedispenser, as shown and described.
FIG. 1 is a front perspective view of a cartridge for a beverage dispenser;
FIG. 2 is a rear perspective view thereof;
FIG. 3 is a front elevation view thereof;
FIG. 4 is a rear elevation view thereof;
FIG. 5 is a right side elevation view thereof;
FIG. 6 is a left side elevation view thereof;
FIG. 7 is a top plan view thereof; and,
FIG. 8 is a bottom plan view thereof.
The dashed lines are included for the purpose of illustrating portions of the cartridge for a beverage dispenser and form no part of the claimed design.