install dependencies in virtual env

.gitlab-ci.yml

@@ -6,6 +6,7 @@ workflow:
 
 variables:
   PIP_CACHE_DIR: "$CI_PROJECT_DIR/.cache/pip"
+  VIRTUAL_ENV: "$CI_PROJECT_DIR/.venv"
   FF_USE_FASTZIP: "true"
 
 stages:
@@ -18,14 +19,20 @@ stages:
     key:
       files:
         - setup.py
+        - requirements.txt
     paths:
       - .cache/pip
+      - ${VIRTUAL_ENV}
+
+before_script:
+  - export PATH="${VIRTUAL_ENV}:$PATH"
 
 requirements:
   extends: .pip cache template
   image: python:3.10-alpine
   stage: install
   script:
+    - python3 -m venv "${VIRTUAL_ENV}"
     - pip install -r requirements.txt
   cache:
     policy: pull-push