Unit test shouldn't fail in GitLab CI

In Briar GTK, this stage is failing for a reason I don't understand: briar-gtk#2 (closed)

Here, it seems to work.

.gitlab-ci.yml

@@ -23,4 +23,3 @@ pytest:
     stage: test
     coverage: '/TOTAL.*\s+(\d+%)$/'
     script: tools/tests/test-pytest.sh
-    allow_failure: true