Bump zope-interface from 5.4.0 to 6.4.post2

Bumps [zope-interface](https://github.com/zopefoundation/zope.interface) from 5.4.0 to 6.4.post2.
- [Changelog](https://github.com/zopefoundation/zope.interface/blob/master/CHANGES.rst)
- [Commits](zopefoundation/zope.interface@5.4.0...6.4.post2)

---
updated-dependencies:
- dependency-name: zope-interface
  dependency-type: indirect
  update-type: version-update:semver-major
...

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