Drop support for Python 3.6.

It's in security fix only mode (till EOY) and doesn't support
module-level __getattr__ yet, which presents enough of a minor
nuisance to drop it.

Users should stick to older jsonschema versions (which should be
properly marked.)

Author: Julian

.github/workflows/ci.yml

@@ -29,18 +29,6 @@ jobs:
             toxenv: pypy3-format_nongpl-build
           - name: pypy-3.7
             toxenv: pypy3-format_nongpl-tests
-          - name: 3.6
-            toxenv: py36-noextra-build
-          - name: 3.6
-            toxenv: py36-noextra-tests
-          - name: 3.6
-            toxenv: py36-format-build
-          - name: 3.6
-            toxenv: py36-format-tests
-          - name: 3.6
-            toxenv: py36-format_nongpl-build
-          - name: 3.6
-            toxenv: py36-format_nongpl-tests
           - name: 3.7
             toxenv: py37-noextra-build
           - name: 3.7

setup.cfg

@@ -15,13 +15,12 @@ classifiers =
     License :: OSI Approved :: MIT License
     Operating System :: OS Independent
     Programming Language :: Python
-    Programming Language :: Python :: 3.6
     Programming Language :: Python :: 3.7
     Programming Language :: Python :: 3.8
     Programming Language :: Python :: 3.9
     Programming Language :: Python :: Implementation :: CPython
     Programming Language :: Python :: Implementation :: PyPy
-python_requires = ">=3.6"
+python_requires = ">=3.7"
 
 [options]
 packages = find:
@@ -39,7 +38,7 @@ format =
     strict-rfc3339
     webcolors
     uri_template
-    isoduration;python_version>'3.6'
+    isoduration
 format_nongpl =
     fqdn
     idna
@@ -48,7 +47,7 @@ format_nongpl =
     rfc3986-validator>0.1.0
     rfc3339-validator
     uri_template
-    isoduration;python_version>'3.6'
+    isoduration
 
 [options.entry_points]
 console_scripts =

tox.ini

@@ -1,6 +1,6 @@
 [tox]
 envlist =
-    py{36,37,38,39,py3}-{noextra,format,format_nongpl}-{build,tests},
+    py{37,38,39,py3}-{noextra,format,format_nongpl}-{build,tests},
     readme
     safety
     secrets