Use collections.abc.Sequence instead of deprecated collections.Sequence.

[bdice]

Hi cuGraph team! I was looking at a couple things across RAPIDS related to Python 3.10 compatibility. There is one spot where the deprecated name collections.Sequence is used. This was moved to collections.abc.Sequence in Python 3.3 and has been deprecated for a while. In Python 3.10 the deprecated names for abstract base classes like collections.Sequence were removed.

This PR fixes that module path to help with eventual compatibility with Python 3.10+. I think this is the only instance of this deprecated name across RAPIDS packages.

(I don't have permissions to set labels or project boards, so the label checker will fail until someone else does that.)

[codecov-commenter]

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[rlratzel]

Thank you for this PR @bdice

[rlratzel]

@gpucibot merge