PyO3 0.20.2

This release corrects a failure to compile of the either feature when the experimental-inspect feature is not enabled.

It also adds backwards-compatibility for pyo3 0.20.0 to build against pyo3-build-config 0.20.2, as pyo3 0.20.0 was (unintentionally) not pinned against an exact patch version pyo3-build-config, and pyo3 0.20.0 could not build against pyo3-build-config 0.20.1 due to an internal API adjustment.

Thank you to the following users for the improvements:

@adamreichold
@davidhewitt