Revert "[CI] don't use a venv in test step"

This reverts commit dec838c76d.

.woodpecker/workflow.yaml

@@ -15,6 +15,9 @@ steps:
       DEPLOYMENT: Test
       ENV_PATH: .env.ci
     commands:
+      - python -m venv venv
+      - /bin/bash -c "source venv/bin/activate"
+      - echo VENV is $VIRTUAL_ENV
       - python -m pip install --root-user-action=ignore --disable-pip-version-check --no-input --quiet -r requirements/test.txt
       - python -m pytest