Drop support for EOL Python 3.6

Author: dbowring

.travis.yml

@@ -4,8 +4,6 @@ cache: pip
 
 matrix:
   include:
-    - name: "Python 3.6 on Linux"
-      python: 3.6
     - name: "Python 3.7 on Linux"
       python: 3.7
     - name: "Python 3.8 on Linux"

setup.py

@@ -66,7 +66,6 @@ def find_version(*file_paths):
         "Topic :: Software Development :: Libraries :: Python Modules",
         "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",

tox.ini

@@ -5,7 +5,7 @@
 
 [tox]
 envlist =
-    py{36,37,38,39,310,py3}, doc
+    py{38,39,310,py,py3}, doc
 skip_missing_interpreters =
     True