Pyg without pyg-lib

[denadai2]

Dear developers,
why are we firing this message

pytorch_geometric/torch_geometric/sampler/neighbor_sampler.py

Line 57 in f0c9fed

if not torch_geometric.typing.WITH_PYG_LIB and sys.platform == 'linux':

if pyg-lib does not support non-directed graphs? Isn't it too early?

[rusty1s]

That's a good point. Let me remove this warning in case directed=False.

[rusty1s]

I fixed this in #7468.