The ornamental design for a piñata greetingcard, as shown and described.
FIG. 1 is a front perspective view of the piñata greeting card of the present invention.
FIG. 2 is a rear perspective view of the piñata greeting card of FIG. 1.
FIG. 3 is a front view of the piñata greeting card of FIG. 1.
FIG. 4 is a rear view of the piñata greeting card of FIG. 1.
FIG. 5 is a left side view of the piñata greeting card of FIG. 1.
FIG. 6 is a right side view of the piñata greeting card of FIG. 1.
FIG. 7 is a top down view of the piñata greeting card of FIG. 1.
FIG. 8 is a bottom up view of the piñata greeting card of FIG. 1.
FIG. 9 is a front perspective view of the piñata greeting card of FIG. 1, with extended telescoping panels; and,
FIG. 10 is a front view of the piñata greeting card of FIG. 1, with extended telescoping panels.
The broken line showing of portions of the piñata greeting card is included for the purpose of illustrating environmental structure and forms no part of the claimed design.