CI: make REUSE lint failures breaking

libeigen/eigen!2524

Co-authored-by: Rasmus Munk Larsen <rmlarsen@gmail.com>

ci/checkformat.gitlab-ci.yml

diff --git a/ci/checkformat.gitlab-ci.yml b/ci/checkformat.gitlab-ci.yml
index 8ab6d29..1dd9c8e 100644
--- a/ci/checkformat.gitlab-ci.yml
+++ b/ci/checkformat.gitlab-ci.yml
@@ -28,7 +28,6 @@
   image: alpine:3.20
   only:
     - merge_requests
-  allow_failure: true
   before_script:
     - apk add --no-cache py3-pip
     - pip install --break-system-packages reuse