* Parse ` type: ...` comments if on Python 3.8+ (jingw, 220).
* Bump minimum Python version to 3.6 (Jendrik Seipp, 218). The last
Vulture release that supports Python 2.7 and Python 3.5 is version 1.6.
* Consider all files under `test` or `tests` directories test files
(Jendrik Seipp).
* Ignore `logging.Logger.propagate` attribute (Jendrik Seipp).