The ornamental design for an uninterruptiblepowersupply, as shown and described.
FIG. 1 is a partial front and left perspective view of an uninterruptible power supply showing the new design; and,
FIG. 2 is a front elevational view of that shown in FIG. 1.
The broken lines shown represent the portions of the uninterruptible power supply that form no part of the claimed design. The dot-dash broken lines define the bounds of the claimed design and form no part thereof.