The ornamental design for a bucket, as shown and described.
FIG. 1 is an illustration of a top perspective view of a bucket showing my new design.
FIG. 2 is an illustration of a front elevational view thereof.
FIG. 3 is an illustration of a rear elevational view thereof.
FIG. 4 is an illustration of a top plan view thereof.
FIG. 5 is an illustration of a bottom plan view thereof.
FIG. 6 is an illustration of a left side elevational view thereof.
FIG. 7 is an illustration of a right side elevational view thereof.
FIG. 8 is an illustration of a top perspective view thereof and shows the lid of the bucket open; and,
FIG. 9 is a side view thereof and shows the bucket on a dolly.
The broken lines showing a dolly are for the purpose of illustrating environmental structure and unclaimed subject matter and form no part of the claimed design.