Update Travis config to resolve Python version

.travis.yml

@@ -14,7 +14,7 @@ before_install:
   - rm -rf dist && python setup.py sdist # prep package distribution
 install:
   - pip install dist/*.tar.gz # install dependencies as specified in setup.py
-  - pip install -r test_requirements.txt
+  - pip install -r test_requirements_`echo $TRAVIS_PYTHON_VERSION | cut -f 1 -d .`.txt
 script:
   - pytest
 after_success:

MANIFEST.in

@@ -1 +1 @@
-include *requirements.txt
+include *requirements*.txt

setup.py

@@ -3,6 +3,7 @@ from __future__ import unicode_literals
 import codecs
 import os
 import re
+import sys
 from distutils.core import setup
 
 from setuptools import find_packages
@@ -33,7 +34,9 @@ setup(
     url = 'https://github.com/monero-ecosystem/monero-python/',
     long_description = open('README.rst', 'rb').read().decode('utf-8'),
     install_requires = open('requirements.txt', 'r').read().splitlines(),
-    tests_require=open('test_requirements.txt', 'r').read().splitlines(),
+    tests_require=open(
+        'test_requirements_py{:d}.txt'.format(sys.version_info.major),
+        'r').read().splitlines(),
     setup_requires=[
         'pytest-runner',
     ],

test_requirements_py2.txt

@@ -0,0 +1,7 @@
+coverage~=5.3
+coveralls~=1.11
+pip>=9
+pytest-cov~=2.10
+pytest-runner~=5.2
+pytest~=4.6
+responses~=0.12