Support Cython 3.0

[ekimd]

_capsule_destructor can no longer be implicitly converted to PyCapsule_Destructor unless it is marked as not throwing an exception.

[oleksandr-pavlyk]

But the function that this change decorates as noexcept does raise Python exceptions. These get now swallowed, or were they being swallowed in 0.29.* as well?

[ekimd]

While I'm not 100% certain, based on some of my reading I believe that the exception would be swallowed in <=0.29.*.
In general, destructors shouldn't throw exceptions otherwise unpredictable behavior can result. Line 57 should perhaps be changed to a simple print instead, or something to that effect.

[oleksandr-pavlyk]

Ok, I will change the source code for the destructor in a separate commit. Thank you for the contribution!