The ornamental design for a holster, as shown and described.
FIG. 1 is a top perspective view of the holster of the present invention;
FIG. 2 is a front elevation view thereof;
FIG. 3 is a rear elevation view thereof;
FIG. 4 is a right side elevation view thereof;
FIG. 5 is a left side elevation view thereof;
FIG. 6 is a top plan view thereof; and,
FIG. 7 is a bottom plan view thereof.
The evenly spaced broken lines shown in the drawings are directed to environment, are for informational purposes only, and form no part of the claimed design. The long and short broken lines are boundary lines which define the bounds of the claimed design. These boundaries do not exist in reality in the article embodying the design. It is understood that the claimed design extends to these boundaries but do not include the boundaries.
The surface shading lines are provided only to indicate the character and/or any contour or curvature of the surfaces. They do not indicate color, texture, markings that actually exist thereon, indicia, graphic representations, surface treatment, or any other ornamentation applied to the article.