The ornamental design for an endcap for a package with flexible walls, as shown and described.
FIG. 1 is a perspective view of the end cap, showing the new design. As shown, the end cap is oriented to show the front side of the end cap;
FIG. 2 is a plan view of the front side of the end cap;
FIG. 3 is plan view of the back side of the end cap;
FIG. 4 is a side elevational view of the end cap (as viewed from the right side of FIG. 1);
FIG. 5 is a side elevational view of the end cap (as viewed from the left side of FIG. 1);
FIG. 6 is an elevational view of the top of the end cap (as viewed from above FIG. 1); and,
FIG. 7 is an elevational view of the bottom of the end cap (as viewed from below FIG. 1).
The broken lines in the drawings are shown for illustrative purposes only and form no part of the claimed design. In addition, the surface shading illustrated in the drawings is provided merely to highlight the contour of design; it is not intended to be illustrative of texture or gloss.