Beverage Container Cap

FIG. 1 is a top front isometric view of a beverage container cap showing the design; FIG. 2 is a bottom rear isometric 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 shading lines shown in the drawings represent the three-dimensional contour of the claimed design and are not intended to indicate surface decoration. The dashed lines shown in the drawings illustrate portions of the beverage container cap that form no part of the claimed design.