What does this PR do?

Update Pytorch version requirement to be above 1.7.0 but skip 1.8.0

Summary

Previously, we had to limit Pytorch to 1.7.1 b/c 1.8.0 broke backward compatability for LSTM models. This has been fixed in 1.9.0, so we can just skip 1.8 versions.

Changes

• Change Pytorch version to be above 1.7.0 but skip 1.8.0

Checklist

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