Twisted 21.7.0rc3

Twisted 21.7.0.rc3 (2021-07-23)

Bugfixes

• The changes to DelayedCall.__repr__ and LoopingCall.__repr__ from
  21.7.0.rc1 were reverted as the wrong assumption that __qualname__ is
  available on all the supported Python versions.
  (#10235)
• The automated release process was updated to generate and release wheel files
  to PyPy (#10236)