Bump the poetry version to 1.0.0

This bumps the poetry version to 1.0.0 so that we can use `poetry.toml` to
configure the in-project setting. See
python-poetry/poetry#1272 for details.

Merges #6

.circleci/config.yml

@@ -43,7 +43,7 @@ jobs:
           command: |
             virtualenv .venv
             . .venv/bin/activate
-            pip install tox
+            pip install tox poetry==1.0.0b4
             tox -e py38-init
       - save_cache:
           key: dysco-python-3.8-{{ .Branch }}-{{ .Revision }}
@@ -100,7 +100,7 @@ jobs:
           command: |
             virtualenv .venv
             . .venv/bin/activate
-            pip install tox
+            pip install tox poetry==1.0.0b4
             tox -e py37-init
       - save_cache:
           key: dysco-python-3.7-{{ .Branch }}-{{ .Revision }}

README.md

@@ -7,7 +7,7 @@ To install the dependencies locally, you need [poetry](https://poetry.eustace.io
 You can then run
 
 ```bash
-# This is optional, but highly recommended.
+# This is only required if you're not using poetry v1.0.0 or greater.
 # It tells poetry to place the virtual environment in `.venv`.
 poetry config settings.virtualenvs.in-project true