Remove that concurrency pip package

- we needed that so traces worked in --parallel
- but we turned that off because 🔥
- thanks :dhaynes:

.gitlab-ci.yml

@@ -26,7 +26,6 @@ before_script:
   - python manage.py makemigrations go
   - python manage.py migrate
   - echo "from django.contrib.auth import get_user_model; User = get_user_model(); User.objects.create_superuser('root', 'root@srct.gmu.edu', 'root') " | python manage.py shell
-  - pip install tblib
 
 Go-py2.7:
   image: library/python:2.7