Support non ASCII attribute

[dozen]

String#undump is a function that does the reverse of String#dump, so we expect String#dump output.

Multibyte characters in terraform_pran results are not escaped. They differ from the results of String#dump (String#dump converts non ASCII characters to Unicode escape sequences).

example:

puts 'hello, 世界'.dump              # => "hello, \u4E16\u754C"
puts '"hello, \u4E16\u754C"'.undump # => hello, 世界
puts '"hello, 世界"'
# Traceback (most recent call last):
#   1: from sample.rb:3:in `<main>'
# sample.rb:3:in `undump': non-ASCII character detected (RuntimeError)

[sds]

Thanks for the fix, @dozen!