Switch to pipenv for release automation

Author: gmorpheme

.circleci/config.yml

@@ -91,11 +91,13 @@ jobs:
     steps:
       - checkout
       - run: |
-          pip3 install -r ci/requirements.txt
+          cd ci
+          pipenv install
       - attach_workspace:
           at: /tmp/workspace
       - run: |
-          ci/release.py /tmp/workspace/dist/x86_64-linux/Cabal-2.0.1.0/build/eu/eu
+          cd ci
+          pipenv run python release.py /tmp/workspace/dist/x86_64-linux/Cabal-2.0.1.0/build/eu/eu
 
 workflows:
   version: 2

ci/Pipfile

@@ -0,0 +1,12 @@
+[[source]]
+url = "https://pypi.org/simple"
+verify_ssl = true
+name = "pypi"
+
+[packages]
+"github3.py" = "*"
+
+[dev-packages]
+
+[requires]
+python_version = "3.6"