The ornamental design for popsicle holder, as shown and described.
FIG. 1 is a front view of a popsicle holder in accordance with the new design;
FIG. 2 is a side view thereof;
FIG. 3 is a top view thereof;
FIG. 4 is a front perpective view thereof; and,
FIG. 5 is a bottom perspective view thereof.
The body portion of the popsicle holder is semi-transparent. The handle of the popsicle holder is opaque. Transparency is omitted in FIGS. 5 and 6 for clarity.