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

acme/acme/__init__.py

@@ -6,7 +6,6 @@ This module is an implementation of the `ACME protocol`_.
 
 """
 import sys
-import warnings
 
 # This code exists to keep backwards compatibility with people using acme.jose
 # before it became the standalone josepy package.
@@ -20,11 +19,3 @@ 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, 6):
-    warnings.warn(
-            "Python 3.6 support will be dropped in the next release of "
-            "acme. Please upgrade your Python version.",
-            PendingDeprecationWarning,
-    )  # pragma: no cover

acme/setup.py

@@ -10,10 +10,10 @@ install_requires = [
     'josepy>=1.10.0',
     'PyOpenSSL>=17.3.0',
     'pyrfc3339',
-    'pytz',
-    'requests>=2.14.2',
+    'pytz>=2019.3',
+    'requests>=2.20.0',
     'requests-toolbelt>=0.3.0',
-    'setuptools>=39.0.1',
+    'setuptools>=41.6.0',
 ]
 
 docs_extras = [
@@ -35,14 +35,13 @@ setup(
     author="Certbot Project",
     author_email='certbot-dev@eff.org',
     license='Apache License 2.0',
-    python_requires='>=3.6',
+    python_requires='>=3.7',
     classifiers=[
         'Development Status :: 5 - Production/Stable',
         'Intended Audience :: Developers',
         'License :: OSI Approved :: Apache Software License',
         'Programming Language :: Python',
         'Programming Language :: Python :: 3',
-        'Programming Language :: Python :: 3.6',
         'Programming Language :: Python :: 3.7',
         'Programming Language :: Python :: 3.8',
         'Programming Language :: Python :: 3.9',