Deprecation warnings for Python 3.4 (#7378)

Fixes #7367

* Deprecation warnings for Python 3.4 users

* CHANGELOG.md and AUTHORS.md

* double equals typo

AUTHORS.md

@@ -230,6 +230,7 @@ Authors
 * [Stavros Korokithakis](https://github.com/skorokithakis)
 * [Stefan Weil](https://github.com/stweil)
 * [Steve Desmond](https://github.com/stevedesmond-ca)
+* [sydneyli](https://github.com/sydneyli)
 * [Tan Jay Jun](https://github.com/jayjun)
 * [Tapple Gao](https://github.com/tapple)
 * [Telepenin Nikolay](https://github.com/telepenin)

CHANGELOG.md

@@ -10,6 +10,8 @@ Certbot adheres to [Semantic Versioning](https://semver.org/).
 
 ### Changed
 
+* We deprecated support for Python 3.4 in Certbot and its ACME library. Support
+  for Python 3.4 will be removed in the next major release of Certbot.
 * Removed `--fast` flag from the test farm tests
 * `--server` may now be combined with `--dry-run`. Certbot will, as before, use the
   staging server instead of the live server when `--dry-run` is used.

acme/acme/__init__.py

@@ -48,3 +48,10 @@ class _TLSSNI01DeprecationModule(object):
 
     def __dir__(self):  # pragma: no cover
         return ['_module'] + dir(self._module)
+
+if sys.version_info[:2] == (3, 4):
+    warnings.warn(
+            "Python 3.4 support will be dropped in the next release of "
+            "acme. Please upgrade your Python version.",
+            PendingDeprecationWarning,
+    ) # pragma: no cover

certbot/main.py

@@ -1368,6 +1368,10 @@ def main(cli_args=None):
         if config.func != plugins_cmd:
             raise
 
+    if sys.version_info[:2] == (3, 4):
+        logger.warning("Python 3.4 support will be dropped in the next release "
+                    "of Certbot - please upgrade your Python version.")
+
     set_displayer(config)
 
     # Reporter