fix: rollback action poetry (#2891)

It seems that the version v4 has been deleted, we are rolling back to v3.

Author: thomaspoignant

.github/workflows/ci.yml

@@ -181,7 +181,7 @@ jobs:
           python-version: 3.9
       - name: Setup Poetry
         if: steps.changed-files-specific.outputs.any_changed == 'true'
-        uses: abatilo/actions-poetry@v4
+        uses: abatilo/actions-poetry@v3
       - name: Poetry install
         if: steps.changed-files-specific.outputs.any_changed == 'true'
         working-directory: ./openfeature/providers/python-provider