CI: Use Python 3.6.5 environment for packaging

Author: effigies

.circleci/config.yml

@@ -339,6 +339,7 @@ jobs:
       - run:
           name: Check pypi preconditions
           command: |
+            pyenv local 3.6.5
             pip install --upgrade pip twine future wheel readme_renderer setuptools
             python setup.py sdist bdist_wheel
             twine check dist/*
@@ -353,7 +354,7 @@ jobs:
       - run:
           name: Validate Python 3 installation
           command: |
-            pyenv local 3.5.2
+            pyenv local 3.6.5
             pip install --upgrade pip
             pip install dist/nipype-*-py2.py3-none-any.whl
             # Futures should not install in Python 3
@@ -388,6 +389,7 @@ jobs:
       - run:
           name: Deploy to PyPI
           command: |
+            pyenv local 3.6.5
             pip install --upgrade twine future wheel readme_renderer setuptools
             python setup.py check -r -s
             python setup.py sdist bdist_wheel