(ci) Introduce tests:3.11 job (#194)

Set default PYTHON_VERSION to 3.11

.gitlab-ci.yml

@@ -6,7 +6,7 @@ stages:
 
 variables:
   DOCKER_IMAGE: "registry.duniter.org/docker/python3/poetry"
-  PYTHON_VERSION: "3.9"
+  PYTHON_VERSION: "3.11"
 
 image: $DOCKER_IMAGE/$PYTHON_VERSION:latest
 
@@ -104,6 +104,8 @@ tests:3.8:
 tests:3.9:cov:
   extends: .tests
   tags: [redshift]
+  variables:
+    PYTHON_VERSION: "3.9"
   script:
     - poetry install
     - poetry run pytest --cov duniterpy --cov-report html:cov_html --cov-report term
@@ -114,6 +116,9 @@ tests:3.10:
   variables:
     PYTHON_VERSION: "3.10"
 
+tests:3.11:
+  extends: .tests
+
 release:
   stage: release
   script: