test/base: adopt newly revamped setup()

Author: gaelicWizard

test/plugins/base.plugin.bats

@@ -1,9 +1,9 @@
-#!/usr/bin/env bats
+# shellcheck shell=bats
 
 load "${MAIN_BASH_IT_DIR?}/test/test_helper.bash"
 
-function local_setup() {
-  setup_libs
+function local_setup_file() {
+  setup_libs "helpers"
   load "${BASH_IT?}/plugins/available/base.plugin.bash"
 }