I claim the ornamental design for a foldable yoga mat, as shown and described.
FIG. 1 is a perspective view of a foldable yoga mat, illustrated in a flat configuration, showing my new design;
FIG. 2 is a top plan view of the invention, illustrated in the flat configuration, the bottom plan view being a mirror image thereof;
FIG. 3 is a left-side elevational view of the invention, illustrated in the flat configuration, the right-side elevational view being a mirror image thereof;
FIG. 4 is a front elevational view of the invention, illustrated in the flat configuration, the rear elevational view being a mirror image thereof; and,
FIG. 5 is a perspective view of the invention, illustrated in an alternate, folded configuration.