Log Message:
py-zope.proxy: updated to 4.3.5

4.3.5:
- Stop installing C header files on PyPy (which is what zope.proxy before 4.3.4
  used to do)

4.3.4:
- Fix a compilation warning on Python 3.8. The slot ``tp_print``
  changed to ``tp_vectorcall_offset`` in 3.8 and must not be set.
  Prior to 3.8, it was reserved and ignored in all Python 3 versions.
- Remove deprecated use of setuptools features.

4.3.3:
- Add support for Python 3.8.
- Drop support for Python 3.4.

4.3.2:
- Fix error handling in ``ProxyBase.__setattr__``: any the exception raised by
  ``PyString_AsString``/``PyUnicode_AsUTF8`` would be silently swallowed up
  and ignored.