Start converting src/x509/verify.rs to new pyo3 APIs

[facutuesca]

Part of #10676

This fixes all except one of the migration warnings for src/x509/verify.rs. The remaining warning should be fixed by the changes on verify.rs on this PR: link

cc @alex @reaperhulk

[facutuesca]

Ah hold off the review, I pushed too early, still need to fix a couple of errors

[facutuesca]

@alex Done, please check the last commit: I had to remove a call to Bound::to_str because it's not supported in Python < 3.10.
The change is:

// before
        let value = subject
            .getattr(pyo3::intern!(py, "value"))?
            .downcast::<pyo3::types::PyString>()?
            .clone();
        Ok(SubjectOwner::DNSName(value.to_str()?.to_owned()))

// after
        let value = subject
            .getattr(pyo3::intern!(py, "value"))?
            .extract::<String>()?;
        Ok(SubjectOwner::DNSName(value))

So I changed the downcast + clone to a extract::<String>() call. Do you think that makes sense?

[alex]

I don't think this clone is required.

[facutuesca]

good catch, fixed!

[alex]

Can you add a comment reminding us that when our minimum python is 3.10, we can switch to borrowing the str.

[facutuesca]

done

[facutuesca]

Looks like a GHA error on one of the runners:

INTERNALERROR>   File "/home/runner/work/cryptography/cryptography/.nox/tests-nocoverage/lib/pypy3.10/site-packages/xdist/dsession.py", line 137, in loop_once
INTERNALERROR>     raise RuntimeError("Unexpectedly no active workers available")
INTERNALERROR> RuntimeError: Unexpectedly no active workers available