Add git diff for test.

.gitlab-ci.yml

@@ -54,6 +54,7 @@ sync_with_openfisca_france:
     - git config --global user.name "OpenFisca-France Reforms CI"
 
     - git switch master
+    - git diff
     - git remote set-url origin git@git.leximpact.dev:openfisca/openfisca-france-reforms.git
 
     - npm install