The ornamental design for postage label, as shown and described.
FIG. 1 is a top plan view of a postage label showing my new design;
FIG. 2 is a right side elevational view thereof, the left side elevational
view being identical;
FIG. 3 is a rear elevational view thereof, the front elevational view being
identical;
FIG. 4 is a bottom plan view thereof; and,
FIG. 5 is an enlargement of a portion of a line of microprinting located
beneath the phrase "U.S. Postage" in FIG. 1, the content of the line of
microprinting forming no part of the claimed design.