The ornamental design for a connector, as shown and described.
FIG. 1 is a perspective view taken from a top, front, right side of a connector; and,
FIG. 2 is a front elevation view thereof.
The dash dot lines immediately adjacent to the shaded areas in the views represent the boundaries of the claimed design. The dashed lines in the figures illustrate the portions of the design that form no part of the claimed design. None of the broken lines form any part of the claimed design.