There is currently no automated process for cleaning outdated or unused dependencies from a package in a single action.
You may use the Dependency Manager to review all missing dependencies. Right-click on a package in the Explorer and select the 'Dependency Manager' option in the contextual menu.
In the manager, right-click on dependency items for a list of actions you may perform on them. The available actions depend for instance on whether the dependency is used or missing.
Let me know if this tool was helpful.
Luca Giarrizzo | QA Analyst, 3D & Immersive | Adobe