Drop Python 3.6 support (#9216)

* Remove deprecation warnings

* update ci

* update setup.py files

* update changelog

* update pinnings

* update requests and friends

* update setuptools pin

* update setuptools pin pt2

* update pytz

* upgrade pyparsing

* upgrade boto deps

* update deps and docs

* update pyproject.toml comment

* remove trailets pin

* remove explicit PYTHON_VERSION

pytest.ini

@@ -27,8 +27,6 @@
 # 7) botocore's default TLS settings raise deprecation warnings in Python
 #    3.10+, but their values are sane from a security perspective. See
 #    https://github.com/boto/botocore/issues/2550.
-# 8) Ignore our own PendingDeprecationWarning about Python 3.6 soon to be dropped.
-#    See https://github.com/certbot/certbot/pull/9160.
 filterwarnings =
     error
     ignore:The external mock module:PendingDeprecationWarning
@@ -38,4 +36,3 @@ filterwarnings =
     ignore:decodestring\(\) is a deprecated alias:DeprecationWarning:dns
     ignore:_SixMetaPathImporter.:ImportWarning
     ignore:ssl.PROTOCOL_TLS:DeprecationWarning:botocore
-    ignore:Python 3.6 support will be dropped:PendingDeprecationWarning