Drop 2.7 Support? #1926
Description
Python will officially drop support for PY27 on January 1, 2020 (as documented), which is less than 3 weeks away. Presumably we should drop support as well.
I had intended for the next release (1.1.0) to maintain support for PY27, but given the long delay in getting it out, I don't think it makes sense anymore. I expect the 1.1.x series to remain current for some time and it doesn't make sense to continue to support PY27 past the next release.
Additionally, in #1797 we introduced a check for FileNotFoundError and that error does not exist in 27 (it is PY3 only). Therefore, the "deploy" command will no longer run on PY27. We missed it in the tests because calls to the system are mocked in the tests. The Appveyor Flake8 test caught it, but I ignored that because I hadn't realized that a previous error with Appveyor which I not understood seems to have resolved itself. The Travis tests were switched to PY3 a while ago in #1782.
As the code doesn't run in PY27 anyway, we should probably run asottile/pyupgrade (with the command pyupgrade --py3-plus) on the code to convert everything to PY3 specific syntax. We also need to audit any TODO comments for any additional changes previously noted.