Remove Python 2.7 compatibility

Fixes #95.

- Remove example/python2
- Make travis and tox pyenvs match setup.py
- Revert to built-in open in setup.py
- Remove caps on transitive dependencies in setup.py

Author: agurgel-te

.travis.yml

@@ -1,13 +1,12 @@
 dist: xenial
 language: python
 python:
-  - "2.7"
   - "3.5"
   - "3.6"
   - "3.7"
   - "3.8"
 install:
-  - pip install -U pip pytest # python 2.7 requires pytest 4
+  - pip install -U pip
   - python setup.py install
   - pip install flake8
   - pip install -r requirements-dev.txt

example/python2/README.rst

@@ -9,9 +9,7 @@
 # Why read it, and not import?
 # see https://groups.google.com/d/topic/pypa-dev/0PkjVpcxTzQ/discussion
 def find_version(*file_paths):
-    # Open in Latin-1 so that we avoid encoding errors.
-    # Use codecs.open for Python 2 compatibility
-    with codecs.open(os.path.join(here, *file_paths), 'r', 'latin1') as f:
+    with open(os.path.join(here, *file_paths), 'r') as f:
         version_file = f.read()
 
     # The version line must have the form
@@ -38,9 +36,6 @@ def find_version(*file_paths):
       install_requires=[
           'flask>=1,<2',
           'pyee>=7,<8',
-          'itsdangerous<2', # for Python 2.7
-          'Jinja2<3', # for Python 2.7
-          'MarkupSafe<2', # for Python 2.7
       ],
       classifiers=[
           'Development Status :: 5 - Production/Stable',
@@ -50,7 +45,6 @@ def find_version(*file_paths):
           'Topic :: Office/Business',
           'License :: OSI Approved :: MIT License',
           'Programming Language :: Python',
-          'Programming Language :: Python :: 2.7',
           'Programming Language :: Python :: 3.5',
           'Programming Language :: Python :: 3.6',
           'Programming Language :: Python :: 3.7',

example/python2/example.py

@@ -4,7 +4,7 @@
 ; for quality analysis, use `tox -e flake8` or just `flake8 slackeventsapi`
 ; to build the docs, use `tox -e docs`
 envlist=
-    py{276,27,34,35,36},
+    py{35,36,37,38},
     flake8,
     docs