The ornamental design for a faucet, as shown and described.
FIG. 1 is a perspective view of a faucet showing my new design;
FIG. 2 is a front elevational view thereof;
FIG. 3 is a rear view thereof;
FIG. 4 is a top plan view thereof;
FIG. 5 is a right side view thereof;
FIG. 6 is a left side view thereof; and,
FIG. 7 is a bottom view thereof.
The broken line showing portions of the claimed design is included for the purpose of illustrating a portion of the faucet that forms no part of the claimed design.