The ornamental design for a mountingbracket, as shown and described.
FIG. 1 is a bottom-left front perspective view of a mounting bracket showing my new design;
FIG. 2 is a front elevation view thereof;
FIG. 3 is a rear elevation view thereof;
FIG. 4 is a left side elevation view thereof;
FIG. 5 is a right side elevation view thereof;
FIG. 6 is a bottom plan view thereof;
FIG. 7 is a top plan view thereof; and,
FIG. 8 is a cross-section view thereof, taken along line 8-8 of FIG. 2.
The dashed broken lines represent unclaimed portions of the article and form no part of the claimed design. The dash-dot-dash lines indicate a boundary of the claim.