The ornamental design for a workstation, as shown and described.
FIG. 1 is a right top front perspective view of a workstation showing our new design;
FIG. 2 is another top-front perspective view of the workstation;
FIG. 3 is a bottom-front perspective view of the workstation;
FIG. 4 is a front view of the workstation;
FIG. 5 is a right side view of the workstation;
FIG. 6 is a top view of the workstation;
FIG. 7 is a bottom view of the workstation;
FIG. 8 is a cross sectional view taken from the direction of section 8-8 of FIG. 4;
FIG. 9 is an enlarged detailed view of encircled area 9 in FIG. 6; and,
FIG. 10 is a left top front perspective view of the workstation.
The broken lines in the FIGURES depict portions of the workstation that form no part of the claimed design. The unshaded surfaces bounded by the broken lines form no part of the claimed design.