I claim the ornamental design for a travel blanket, as shown and described.
FIG. 1 is a front perspective view of a travel blanket, showing my new design in a deployed configuration;
FIG. 2 is a rear perspective view thereof, illustrated in a flat configuration;
FIG. 3 is a rear elevational view of FIG. 2;
FIG. 4 is a front elevational view of FIG. 2;
FIG. 5 is a right-side elevational view of FIG. 2;
FIG. 6 is a left-side elevational view of FIG. 2;
FIG. 7 is a top plan view of FIG. 2; and,
FIG. 8 is a bottom plan view of FIG. 2.
The broken lines showing a stroller in FIG. 1 depict environmental matter and form no part of the claimed design. The remaining broken lines represent stitching, and are part of the claimed design.