ERROR: Unsatisfiable requirements detected for package TrajOptPlots

General Usage
1

when I add TrajOptPlots , I got an error message:

(TrajectoryOptimization-examples) pkg> add TrajOptPlots
    Updating registry at `C:\Users\xxx\.julia\registries\General`
    Updating git-repo `https://github.com/JuliaRegistries/General.git`
   Resolving package versions...
ERROR: Unsatisfiable requirements detected for package TrajOptPlots [7770976a]:
 TrajOptPlots [7770976a] log:
 ├─possible versions are: 0.1.0-0.2.0 or uninstalled
 ├─restricted to versions * by an explicit requirement, leaving only versions 0.1.0-0.2.0
 └─restricted by compatibility requirements with RobotDynamics [38ceca67] to versions: uninstalled — no versions left
   └─RobotDynamics [38ceca67] log:
     ├─possible versions are: 0.0.1-0.4.8 or uninstalled
     └─restricted to versions 0.4.8-0.4 by TrajectoryOptimization [c79d492b], leaving only versions 0.4.8
       └─TrajectoryOptimization [c79d492b] log:
         ├─possible versions are: 0.7.1 or uninstalled
         └─TrajectoryOptimization [c79d492b] is fixed to version 0.7.1

This may have something wrong with version dependency. But I couldn’t install the other versions of the TrajectoryOptimization package because it might cause version dependency issues with the other packages.
How can I solve this problem? What is the proper way to install TrajOptPlots.jl?