Use older version of poetry for sdist

Newer versions forces epoch 0 which is not nice

Author: schaefi

.github/workflows/ci-publish-to-pypi.yml

@@ -28,7 +28,7 @@ jobs:
     - name: Install
       run: |
         python -m pip install --upgrade pip
-        python -m pip install poetry
+        python -m pip install poetry==1.7.1
     - name: Prepare
       run: |
         make prepare_for_pypi