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