Consistent mechanism to install poetry

.circleci/config.yml

@@ -108,10 +108,10 @@ jobs:
       version: "3.7"
     steps:
       - checkout
+      - *install-poetry
       - run:
           name: Push to PyPI
           command: |
-            curl -sSL https://raw.githubusercontent.com/python-poetry/poetry/master/get-poetry.py | python
             source $HOME/.poetry/env
             poetry publish \
               --build \