The ornamental design for a lunchcooler with cinch top, as shown and described.
FIG. 1 is a perspective view of the lunch cooler with cinch top;
FIG. 2 is a front view of the lunch cooler with cinch top;
FIG. 3 is a rear view of the lunch cooler with cinch top;
FIG. 4 is a right side view of the lunch cooler with cinch top;
FIG. 5 is a left side view of the lunch cooler with cinch top;
FIG. 6 is a top view of the lunch cooler with cinch top; and,
FIG. 7 is a bottom view of the lunch cooler with cinch top.
The broken lines showing in the figures are included for the purpose of illustrating portions of the lunch cooler with cinch top that form no part of the claimed design.