Apparently you can't use a Boolean true in gitlab-ci.yml environment variables config

.gitlab-ci.yml

@@ -2,7 +2,7 @@ image: python:3.6
 variables:
   GIT_SUBMODULE_STRATEGY: normal
   PIP_CACHE_DIR: $CI_PROJECT_DIR/.pip-cache
-  PIPENV_VENV_IN_PROJECT: true
+  PIPENV_VENV_IN_PROJECT: yeppers
 
 cache:
   paths: