Fix version error for `pytest-icdiff`.
What's Changed
* Fix version error for `pytest-icdiff` by chrimaho in https://github.com/chrimaho/py-tictoc/pull/12
* Bump version by chrimaho in https://github.com/chrimaho/py-tictoc/pull/13
**Full Changelog**: https://github.com/chrimaho/py-tictoc/compare/v0.1.7...v0.1.8