fix : gitlab shared files ref

.gitlab-ci.yml

@@ -12,7 +12,7 @@ stages:
 
 include:
   - project: 'eclipse/aidge/gitlab_shared_files'
-    ref: 'feat/release_pip'
+    ref: 'main'
     file: 
       # choose which jobs to run by including the corresponding files.
       - '.gitlab/ci/ubuntu_cpp.gitlab-ci.yml'