Hypothesis for Python - version 5.6.0

This release adds an explicit warning for tests that are both
decorated with "@given(...)" and request a function-scoped pytest
fixture, because such fixtures are only executed once for all
Hypothesis test cases and that often causes trouble (issue #377).

It's very difficult to fix this on the pytest side, so since 2015
our advice has been "just don't use function-scoped fixtures with
Hypothesis". Now we detect and warn about the issue at runtime!

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