Merge pull request #26 from nenkoru/poetry-travis-fix

fix: travis ci with poetry

.travis.yml

@@ -3,13 +3,14 @@ python:
   - "3.8"
   - "3.9"
 # command to install dependencies
+before_install:
+  - pip install poetry
 install:
-  - pip install -r requirements.txt
-  - pip install -r requirements_test.txt
-  - pip install pytest-cov
-  - pip install coveralls
+  - poetry install
+  - poetry run pip install pytest-cov
+  - poetry run pip install coveralls
 # command to run tests
 script:
-  - pytest tests --cov=okama/
+  - poetry run pytest tests --cov=okama/
 after_success:
-  - coveralls
+  - poetry run coveralls