The ornamental design for a bowlholder for a cooking robot, as shown and described.
1. Bowl holder for a cooking robot
1.1 : Perspective
1.2 : Front
1.3 : Back
1.4 : Left
1.5 : Right
1.6 : Top
1.7 : Bottom
1.8 : Reference view showing a state of use
The broken lines in FIGS. 1.1, 1.2 and 1.7 depict portions of the bowl holder for a cooking robot that form no part of the claimed design. The broken lines in FIG. 1.8 show environment that forms no part of the claimed design.