Ruby 3 KwArg: Form526 Convert to PDF (#11915)

Ruby 2.7 deprecated automatic casting of a hash passed as the last
argument of a method to keyword arguments. You must now use actual
keyword arguments (`foo(bar: 'baz')` instead of ` foo({bar: 'baz'})`) or cast the hash to a keyword args using the double splat (`foo(**{bar: 'baz'})`).

In preparation for upgrading to Ruby 3.0, we're implementing the new syntax.

lib/form526_backup_submission/utilities/convert_to_pdf.rb

@@ -63,7 +63,7 @@ def convert_txt!
         # We COULD download more fonts if we needed more char/unicode support.
         # But for now sending through with non-'Windows-1252' encoded chars stripped should work.
         # Can expand later if needed.
-        content = File.read(@original_file).encode('Windows-1252', { invalid: :replace, undef: :replace, replace: '' })
+        content = File.read(@original_file).encode('Windows-1252', invalid: :replace, undef: :replace, replace: '')
         Prawn::Document.generate(@converted_filename) do |pdf|
           pdf.text generate_pdf_title_page
           pdf.start_new_page