Made gitlab-ci use the same postgresql version as the user selected at project creation time.

Author: arnav13081994

{{cookiecutter.project_slug}}/.gitlab-ci.yml

@@ -39,7 +39,7 @@ pytest:
   tags:
     - python
   services:
-    - postgres:11
+    - postgres:{{ cookiecutter.postgresql_version }}
   variables:
     DATABASE_URL: pgsql://$POSTGRES_USER:$POSTGRES_PASSWORD@postgres/$POSTGRES_DB