Make Sytle/IndentHeredoc disable
Make Sytle/IndentHeredoc disable

* Style/IndentHeredoc is added on rubocop v0.48.0.
    https://github.com/bbatsov/rubocop/pull/4028
  This commit fixes offenses of this cop.
* Squiggly heredoc(<<~EOS ... EOS) can fix this offense.
  But squiggly heredoc is available since Ruby 2.3.0.
* ActiveSupport String#strip_heredoc can also fix this offense.
  But ActiveSupport is not included in simplecov runtime dependencies.

colszowka/simplecov,colszowka/simplecov