Code Cleanup

[aMahanna]

Warrants a 1.1.2 release

Note: the diff is large due to the output notebook change from 48160f1

Note: For notebook testing purposes:

• Use !pip install git+https://github.com/arangoml/pyg-adapter.git@code-cleanup
• Use !git clone -b code-cleanup --single-branch https://github.com/arangoml/pyg-adapter.git

No functionality changes

What's been done:

• copy changes from arangoml/dgl-adapter@6b36a50
• update rich usage to rely on the rich.live module
• general code cleanup & comments
• improve method readability
• pip install fixes for build.yml & release.yml