I claim the ornamental design for an armored backpack, as shown and described.
FIG. 1 is a front perspective view of an armored backpack, showing my new design;
FIG. 2 is a rear perspective view thereof;
FIG. 3 is a front elevational view thereof;
FIG. 4 is a rear elevational view thereof;
FIG. 5 is a left-side elevational view thereof;
FIG. 6 is a right-side elevational view thereof;
FIG. 7 is a top plan view thereof; and,
FIG. 8 is a bottom plan view thereof.
The broken lines showing a logo in FIGS. 1, 3 and 4 and a cellular phone and a cable in FIG. 2 depict environmental matter and form no part of the claimed design. The remaining broken lines represent stitching, and are part of the claimed design. The zipper track is illustrated in solid line.