[Dataset] Update download links of GRB data (#438)

[Doc] Update v0.6 (#430)

[Example] Add GraphMAE2 (#429)

[Example] Add GraphMAE (#428)

[Feature] Update UnsupGraphsage (#425)

[Example] Update GCC result (#409)

[Example] Add BGRL (#408)

[Feature] Add traffic prediction task (#407)

[Example] Update GRB (#406)

[Model] Update GCC model (#392)

Update README.md

[BugFix] Fix bugs in oagbert.encode_paper (#385)

[Model] Update GraphSAGE (#384)

[Feature] Update KG methods (#381)

[Feature] Update Unsup_Graphsage (#379)