Draft: Merge 3D generator repo history
This is a demo of a git subtree-merge of the 3D generator repo into the 3d-gen
subdirectory
To replicate:
git remote add -f 3dgen https://gitlab.com/kicad/libraries/kicad-packages3D-generator.git
git merge -s ours --no-commit 3dgen/master --allow-unrelated-histories
git read-tree --prefix=3d-gen -u 3dgen/master
git cm -m "Merged 3D generator repo (with history) to 3d-gen directory"