New and faster installer implementation

.cirrus.yml

@@ -16,7 +16,8 @@ test_task:
     - pkg install -y git-lite $PYPACKAGE $SQLPACKAGE
   pip_script:
     - $PYTHON -m ensurepip
-    - $PYTHON -m pip install -U pip tox poetry
+    - $PYTHON -m pip install -U pip tox
+    - $PYTHON -m pip install -U --pre poetry
     - poetry config virtualenvs.in-project true
   tox_script: $PYTHON -m tox -e py -- -q --junitxml=junit.xml tests
   on_failure:

.flake8

@@ -16,6 +16,7 @@ exclude =
     .vscode
     .github
     poetry/utils/_compat.py
+    poetry/utils/env_scripts/tags.py
     tests/fixtures/
     tests/repositories/fixtures/
     tests/utils/fixtures/

.github/workflows/main.yml

@@ -49,7 +49,7 @@ jobs:
         shell: bash
         run: |
           curl -fsS -o get-poetry.py https://raw.githubusercontent.com/python-poetry/poetry/master/get-poetry.py
-          python get-poetry.py -y
+          python get-poetry.py -y --preview
           echo "::set-env name=PATH::$HOME/.poetry/bin:$PATH"
 
       - name: Configure poetry