The ornamental design for a golfclubbackpack, as shown and described.
FIG. 1 is a perspective view of a golf club backpack showing my new design;
FIG. 2 is a side view thereof;
FIG. 3 is a second side view thereof;
FIG. 4 is a front view thereof;
FIG. 5 is a rear view thereof;
FIG. 6 is a top view thereof; and,
FIG. 7 is a bottom view thereof.
The evenly dashed broken lines illustrate portions of the article and stitching and form no part of the claim. The dash dot dash lines define the bounds of the claim and form no part thereof.