Add Python 3.8 & 3.9 as supported version

Since Py 3.8 & 3.9 is supported, we should update the identified, as it is shown on PIP and gives wrong impressions that Py 3.8 is not supported

Author: kaxil

.github/workflows/run-tests.yml

@@ -17,6 +17,10 @@ jobs:
             tox-env: py36
           - python-version: 3.7
             tox-env: py37,docs,readme,black
+          - python-version: 3.8
+            tox-env: py38
+          - python-version: 3.9
+            tox-env: py39
           - python-version: pypy3
             tox-env: pypy3
     steps:

setup.py

@@ -60,6 +60,8 @@ def readall(path):
         "Programming Language :: Python :: 3.5",
         "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",
     ],

tox.ini

@@ -1,39 +0,0 @@
-[tox]
-envlist=py27,py34,py35,py36,py37,pypy,pypy3,docs,readme,black
-
-[testenv]
-deps=
-    -r{toxinidir}/requirements-test.txt
-commands=coverage run --source=requests_oauthlib -m unittest discover
-
-# special py27 requirements as upstream libraries stopped
-# supporting latest versions
-[testenv:py27]
-deps=
-    -r{toxinidir}/requirements-test-27.txt
-[testenv:pypy]
-deps=
-    -r{toxinidir}/requirements-test-27.txt
-
-# tox -e docs to mimick readthedocs build.
-# should be similar to .readthedocs.yaml pipeline
-[testenv:docs]
-basepython=python3.7
-skipsdist=True
-deps=
-    -r{toxinidir}/docs/requirements.txt
-changedir=docs
-whitelist_externals=make
-commands=make clean html
-
-# tox -e readme to mimick pypi validation of readme/rst files.
-[testenv:readme]
-basepython=python3.7
-deps=twine>=1.12.0
-commands=
-        twine check .tox/dist/*
-
-[testenv:black]
-basepython=python3.7
-deps=black
-commands=black --check .