Updated RotorForge Freecad Workbench to Version 0.20

I updated my Freecad workbench "RotorForge" to version 0.20.

Check the Changelog if you like to know what changed.

Workbench:

https://drive.google.com/file/d/1O0WsdlxP7ISWbGk6QnTbIulqBG--Puqe/view?usp=drive_link

Here is an example of a drone frame:

https://drive.google.com/file/d/1LCUMp0K-JFFMwUnNFWXI4VOGlb3RZ39Y/view?usp=drive_link