Dropping support for Python 3.6
Python 3.6 [has been retired](https://peps.python.org/pep-0494/#lifespan) on December 21st 2021 and won't get new security releases anymore. As a result, Transformers will stop supporting Python 3.6 and have a minimum requirement of Python 3.7 in the next release (v4.19.0), around the beginning of May.
What is the purpose of dropping support while not using latest features of newer python versions (or newer versions of other libraries, which are dropping support)?<|||||>Hey @LSinev, thank you for asking. There are some features that would have been implemented in a simpler manner had Python 3.6 been dropped earlier (https://github.com/huggingface/transformers/issues/15739, @sgugger can chime in on the init system), and we already use features that are only available in 3.7 (`dataclasses`). 

Furthermore:
- Python 3.6 is now EOL and will not be receiving new bug and security patches
- All backends of `transformers` newer versions (torch 1.11, tensorflow 2.8, jax  0.2.18) now require python 3.7<|||||>We were not using the features of newest Python versions without dropping the old ones ;-)
For instance, our inits will now be able to use [PEP 562](https://docs.python.org/3/whatsnew/3.7.html#whatsnew37-pep562) <|||||>This issue has been automatically marked as stale because it has not had recent activity. If you think this still needs to be addressed please comment on this thread.

Please note that issues that do not follow the [contributing guidelines](https://github.com/huggingface/transformers/blob/main/CONTRIBUTING.md) are likely to be ignored.