[Docs] add images

[Version] 0.2.3

[Version] 0.2.2

[Version] 0.2.1 (finally remembered to update it lol)

[Notebooks] add Torch Geometric dependency to graph encoders

[Minor] avoid Codecov fail

Merge pull request ai4co#86 from kaist-silab/refac

`v0.1.0`

[Version] 0.0.6

[Version] 0.0.5

[Version] 0.0.4