- Fix Python 3.8 compatibility issue. - Use ``time.monotonic`` as default timer if available. - Improve documentation regarding thread safety. - Officially support Python 3.7. - Drop Python 3.3 support (breaking change). - Remove ``missing`` cache constructor parameter (breaking change). - Remove ``self`` from ``@cachedmethod`` key arguments (breaking change). - Add support for ``maxsize=None`` in ``cachetools.func`` decorators. OBS-URL: https://build.opensuse.org/package/show/devel:languages:python/python-cachetools?expand=0&rev=12