Rename repository to modelica.org

[t-sommer]

No description provided.

[dietmarw]

Are there any plans to do this rename? I'm asking since I was about to update the link here

www.modelica.org/content/libraries.md

Line 39 in 966a1be

To list your library here, please use the [issue tracker.](https://github.com/modelica/old.modelica.org/issues/new?assignees=dietmarw&labels=&template=new-open-source-library.md&title=Add+open-source+library+%5BLibraryName%5D+to+the+library+listing)

but might just aswell wait if the repo gets renamed yet again.

[dzimmer]

Renaming the repository has not high priority (at least from my side). Updating the link has. Please update the link.