rust-sha256 is unable to migrate to Testing because one of its
autopkgtests is failing. Specifically, the native_openssl autopkgtest.
There are several ways of handling this. Here are some examples.
- maybe there is an error in one or more of the rust functions where
code is marked as not needed for the native_openssl feature but it is
needed. Thefore, the function should be patched
- maybe it is required to use the native_openssl feature with another
feature so debian/tests/control should be updated for that
- or the test failure could simply be ignored by marking the test as
flaky in debian/tests/control.

There is an optional feature in rust-system-deps and
rust-system-deps-meta that could use rust-sha256 but it can't be used
if rust-sha256 is not in Testing.

Thank you,
Jeremy Bícha