Add warnings about Python 3.5 deprecation in Certbot (#8154)

Fixes #8149

This PR adds warnings to warn about the incoming deprecation of Python 3.5 in Certbot.

* Add warnings about Python 3.5 deprecation in Certbot

* Update certbot/certbot/__init__.py

Co-authored-by: Brad Warren <bmw@users.noreply.github.com>

Co-authored-by: Brad Warren <bmw@users.noreply.github.com>

acme/acme/__init__.py

@@ -20,3 +20,11 @@ for mod in list(sys.modules):
     # preserved (acme.jose.* is josepy.*)
     if mod == 'josepy' or mod.startswith('josepy.'):
         sys.modules['acme.' + mod.replace('josepy', 'jose', 1)] = sys.modules[mod]
+
+
+if sys.version_info[:2] == (3, 5):
+    warnings.warn(
+            "Python 3.5 support will be dropped in the next release of "
+            "acme. Please upgrade your Python version.",
+            PendingDeprecationWarning,
+    )  # pragma: no cover

certbot/CHANGELOG.md

@@ -14,6 +14,8 @@ Certbot adheres to [Semantic Versioning](https://semver.org/).
 
 * The Linode DNS plugin now waits 120 seconds for DNS propagation, instead of 1200,
   due to https://www.linode.com/blog/linode/linode-turns-17/
+* We deprecated support for Python 3.5 in Certbot and its ACME library.
+  Support for Python 3.5 will be removed in the next major release of Certbot.
 
 ### Fixed
 

certbot/certbot/__init__.py

@@ -1,4 +1,13 @@
 """Certbot client."""
+import warnings
+import sys
 
 # version number like 1.2.3a0, must have at least 2 parts, like 1.2
 __version__ = '1.7.0.dev0'
+
+if sys.version_info[:2] == (3, 5):
+    warnings.warn(
+            "Python 3.5 support will be dropped in the next release of "
+            "certbot. Please upgrade your Python version.",
+            PendingDeprecationWarning,
+    )  # pragma: no cover

certbot/certbot/_internal/main.py

@@ -1343,6 +1343,10 @@ def main(cli_args=None):
         if config.func != plugins_cmd:  # pylint: disable=comparison-with-callable
             raise
 
+    if sys.version_info[:2] == (3, 5):
+        logger.warning("Python 3.5 support will be dropped in the next release "
+                       "of Certbot - please upgrade your Python version.")
+
     set_displayer(config)
 
     # Reporter