Make reset explicit and public

[dzherb]

Fixed issue #64

The __call_succeeded method already did a reset, so i decided just to rename it.

I could do something like this instead:

def __call_succeeded(self):
    self.reset()

def reset(self):
    self._state = STATE_CLOSED
    self._last_failure = None
    self._failure_count = 0

But i thought there is no point, since __call_succeeded is only called in one place.

And, anyway, there is issue #60 that ideally should bring callbacks on state change. So there is no point to keep __call_succeeded.

[fabfuel]

Thanks Dmitrii! 🙌

[fabfuel]

I have released version 2.1.0 including your change
https://pypi.org/project/circuitbreaker/