diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index be30be966bab1211a069e1a08d2bfd99858456d7..caf8c447066c496e7298edc8bc84d749ddae66a0 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -54,8 +54,10 @@ lint:
   stage: checks
   script:
     - poetry config virtualenvs.in-project true
-    - poetry install --no-dev
+    - poetry install
     - make pylint
+  variables:
+    PYTHON_VERSION: "3.9"
 
 .tests:
   extends: .changes