ci: add resue job to compliance stage

Signed-off-by: Chase Qi <chase.qi@linaro.org>

.gitlab-ci.yml

@@ -23,6 +23,7 @@ dco:
   allow_failure: true
 
 reuse:
+  stage: compliance
   extends: .reuse
   # The repository is not yet reuse compliant and we don't have full control on
   # it - it is a 3rd party fork. Let if fail for now.