The ornamental design for a tubingconnector for a breastmilk system, as shown and described.
FIG. 1 is a perspective view of a tubing connector for a breastmilk system in accordance with the present invention;
FIG. 2 is a top view thereof;
FIG. 3 is a front view thereof, the rear view being a mirror image; and,
FIG. 4 is a bottom view.
The broken lines in the drawing figures form no part of the claimed design. The tubing connector is shown with a symbolic break in its length. The appearance of any portion of the article between the break lines forms no part of the claimed design.