Add a __repr__ method to RetryCallState objects (#302)

* Add a __repr__ method to RetryCallState objects

* Update __init__.py

* Address reviewer comments

* Blacken

* Make python 2 compatible

* Blacken

* Reblacken files

* Switch to f-strings

Co-authored-by: Julien Danjou <julien@danjou.info>
Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>
3 files changed