The ornamental design for a rocket-shaped beverage container, as shown and described.
FIG. 1 is a front elevational view of the rocket-shaped beverage container, wherein the cap and shell portion of the beverage container is shown depicted in dashed broken lines illustrating portions forming no part of the claimed design;
FIG. 2 is a left-side elevational view, which mirrors the right-side elevational view, of the beverage container depicted in FIG. 1;
FIG. 3 is a rear elevational view of the beverage container depicted in FIG. 1;
FIG. 4 is a top plan view of the beverage container depicted in FIG. 1;
FIG. 5 is a bottom plan view of the beverage container depicted in FIG. 1; and,
FIG. 6 is a perspective view of the beverage container depicted in FIG. 1.