Remove python 3.5 support; add python 3.8 support

- Python 3.5 has reached end-of-life.
- Add support for Python 3.8
- Move dist to bionic (xenial is EOL in April)
- Upgrade pip in travis.yml's `before_install`. this should install a wheel
  for pyca/cryptography
- Install rust for pypy builds. It is a requirement for cryptography as no
  pypy wheels exist.

.travis.yml

@@ -1,22 +1,23 @@
 language: python
-python: 3.7
-dist: xenial
+python: 3.8
+dist: bionic
 cache: pip
 matrix:
   include:
-  - python: 3.5
-    env: TOXENV=py35
   - python: 3.6
     env: TOXENV=py36
   - python: 3.7
     env: TOXENV=py37
-  - python: 3.7
+  - python: 3.8
+    env: TOXENV=py38
+  - python: 3.8
     env: TOXENV=bandit
-  - python: pypy3.5
+  - python: pypy3
     env: TOXENV=pypy3
-install:
-- pip install -U setuptools
-- pip install tox coveralls
+before_install:
+  - python -m pip install --upgrade pip setuptools
+  - python -m pip install tox coveralls
+  - if [ "$TOXENV" == "pypy3" ]; then curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y && source $HOME/.cargo/env ; fi
 script: tox
 after_success: COVERALLS_PARALLEL=true coveralls
 notifications:

README.rst

@@ -2,7 +2,7 @@ OAuthLib - Python Framework for OAuth1 & OAuth2
 ===============================================
 
 *A generic, spec-compliant, thorough implementation of the OAuth request-signing
-logic for Python 3.5+.
+logic for Python 3.6+.
 
 .. image:: https://travis-ci.org/oauthlib/oauthlib.svg?branch=master
   :target: https://travis-ci.org/oauthlib/oauthlib

setup.py

@@ -34,7 +34,7 @@ def fread(fn):
     platforms='any',
     license='BSD',
     packages=find_packages(exclude=('docs', 'tests', 'tests.*')),
-    python_requires='>=3.5',
+    python_requires='>=3.6',
     extras_require={
         'rsa': rsa_require,
         'signedtoken': signedtoken_require,
@@ -51,9 +51,9 @@ def fread(fn):
         'Operating System :: POSIX :: Linux',
         'Programming Language :: Python',
         'Programming Language :: Python :: 3',
-        'Programming Language :: Python :: 3.5',
         'Programming Language :: Python :: 3.6',
         'Programming Language :: Python :: 3.7',
+        'Programming Language :: Python :: 3.8',
         'Programming Language :: Python :: 3 :: Only',
         'Programming Language :: Python :: Implementation',
         'Programming Language :: Python :: Implementation :: CPython',

tox.ini

@@ -1,5 +1,5 @@
 [tox]
-envlist = py35,py36,py37,pypy,pypy3,docs,readme,bandit,isort
+envlist = py36,py37,py38,pypy,pypy3,docs,readme,bandit,isort
 
 [testenv]
 deps=
@@ -22,21 +22,21 @@ commands=make clean html
 
 # tox -e readme to mimick PyPI long_description check
 [testenv:readme]
-basepython=python3.7
+basepython=python3.8
 deps=twine>=1.12.0
 whitelist_externals=echo
 commands=
         twine check dist/*
 
 [testenv:bandit]
-basepython=python3.7
+basepython=python3.8
 skipsdist=True
 deps=bandit
 commands=bandit -b bandit.json -r oauthlib/
 whitelist_externals=bandit
 
 [testenv:isort]
-basepython = python3.7
+basepython = python3.8
 usedevelop = false
 deps = isort
 changedir = {toxinidir}