update CI

Author: Remi-Gau

.github/workflows/update_submodules.yml

@@ -85,6 +85,7 @@ jobs:
                   branch=$(git config --get --file .gitmodules submodule.${path}.branch)
                   echo -e "\nswitching submodule ${path} to ${branch}"
                   cd "${path}" || exit
+                  git fetch --all
                   git checkout ${branch}
                   cd "${start_dir}"
               done