We claim the ornamental design for a digital kiosk, as shown and described.
FIG. 1 is a front, top, and right side perspective view showing our new design.
FIG. 2 is a rear, bottom, and left side perspective view thereof.
FIG. 3 is a front view thereof.
FIG. 4 is a rear view thereof.
FIG. 5 is a right view thereof.
FIG. 6 is a left view thereof.
FIG. 7 is a top view thereof; and,
FIG. 8 is a bottom view thereof.
The broken lines shown represent unclaimed subject matter and form no part of the claimed design. The shade lines shown represent surface shading and not surface ornamentation, color, or material type.