scripts: serie_update: fetch submodules

            # if already exists, then just clean and fetch

            self.os_cmd(("git", "clean", "-fdx"), cwd=self.stm32cube_serie_path)

            self.os_cmd(("git", "fetch"), cwd=self.stm32cube_serie_path)

            # this is useful when HAL drivers submodules are not aleardy

            # present locally, otherwise "git fetch" is sufficient

            self.os_cmd(("git", "submodule", "update", "--init"),

                        cwd=self.stm32cube_serie_path)

            branch = self.major_branch()

            self.os_cmd(

                ("git", "reset", "--hard", branch),

                cwd=self.stm32cube_serie_path,

            )

        else:

            # HAL drivers are now included as git submodules in upstream

            # STM32Cube repositories

            # So, we need to add --recursive or --recurse-submodules to

            # "git clone" to fetch them

            self.os_cmd(

                ("git", "clone", repo_name),

                ("git", "clone", "--recursive", repo_name),

                cwd=self.stm32cube_repo_path,

            )

            branch = self.major_branch()