The folder you are referring to ( C:\ProgramData\Objectif Lune\PlanetPress Workflow 8\PlanetPress Watch\OLConnect\ ) contains the OL Connect resources used by Workflow to produce Connect Jobs (Data mapping configs, templates, etc). There’s an Archive Subfolder in there that maintains the list of the 30 last versions of each resource. These folders and their contents are unfortunately not configurable, but if, for instance, you don’t need the Archive folder, you could create a simple process that periodically empties it (or moves its contents elsewhere).
Another folder that may contain a lot of data is the C:\ProgramData\Objectif Lune\PlanetPress Workflow 8\PlanetPress Watch\Log folder. And while you can’t change its location, you have better control over the size (and number) of files it stores. In the preferences (Plug-in|General), you can specify how many days of logging you want to keep. And in each process, you can tick the “Minimal logs on success” option which dramatically reduces the size of the logs (if the process runs without a hitch, barely nothing gets logged, but if there is an issue, then the full log is written as usual).