Apply Rubocop Performance/RedundantSplitRegexpArgument (#23443)

* Apply Rubocop Performance/RedundantSplitRegexpArgument

* Update app/controllers/concerns/signature_verification.rb

app/controllers/concerns/signature_verification.rb

@@ -227,7 +227,7 @@ module SignatureVerification
   end
 
   def to_header_name(name)
-    name.split(/-/).map(&:capitalize).join('-')
+    name.split('-').map(&:capitalize).join('-')
   end
 
   def missing_required_signature_parameters?