DEV: Fix lint.

DEV: Fix lint.

diff --git a/lib/freedom_patches/middleware_stack.rb b/lib/freedom_patches/middleware_stack.rb
index bf9d76f..431fef3 100644
--- a/lib/freedom_patches/middleware_stack.rb
+++ b/lib/freedom_patches/middleware_stack.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # TODO: Remove once we upgrade to Rails 6.1
 # Copied implementation from https://github.com/rails/rails/pull/38169
 module ActionDispatch

GitHub sha: 248db310