The ornamental design for a garment having an opening, as shown and described.
FIGS. 1-4 show a first embodiment of the opening for a garment of our design;
FIG. 1 is a perspective view of an entire garment, showing the opening being claimed with the opening being open of the embodiment thereof;
FIG. 2 is a perspective view of an entire garment, showing the opening being claimed with the opening being closed of the embodiment thereof;
FIG. 3 is a front elevational view with the opening being open of the embodiment thereof;
FIG. 4 is a front elevational view with the opening being closed of the embodiment thereof;
FIGS. 5-8 show a second embodiment of the opening for a garment of our design;
FIG. 5 is a perspective view of an entire garment, showing the opening being claimed with the opening being open of the embodiment thereof;
FIG. 6 is a perspective view of an entire garment, showing the opening being claimed with the opening being closed of the embodiment thereof;
FIG. 7 is a front elevational view with the opening being open of the embodiment thereof; and,
FIG. 8 is a front elevational view with the opening being closed of the embodiment thereof.
The small broken lines illustrating the zippers and stitching and the large broken lines illustrating the remainder of the garment form no part of the claimed design.