DEV: Load rails_helper in pbkdf2_spec (#14775)

DEV: Load rails_helper in pbkdf2_spec (#14775)

Fixes failing tests in CI, where this spec file was first in a batch.

diff --git a/spec/components/pbkdf2_spec.rb b/spec/components/pbkdf2_spec.rb
index 0de2f5e..bbc07c4 100644
--- a/spec/components/pbkdf2_spec.rb
+++ b/spec/components/pbkdf2_spec.rb
@@ -1,5 +1,6 @@
 # frozen_string_literal: true
 
+require 'rails_helper'
 require 'pbkdf2'
 
 describe Pbkdf2 do

GitHub sha: d760c86031eb4368dc458f50d5b3dda6d2146005

This commit appears in #14775 which was approved by eviltrout. It was merged by CvX.