Pin poetry version to 1.7.1

Author: MDUYN

.github/workflows/test.yml

@@ -69,6 +69,7 @@ jobs:
       - name: Install Poetry
         uses: snok/install-poetry@v1
         with:
+          version: 1.7.1
           virtualenvs-create: true
           virtualenvs-in-project: true
       #----------------------------------------------