Reverse dependencies for plain_text

Latest version of the following gems require plain_text

Gem	Version	Date	Downloads
sub_object +9.82 Thousand Downloads	`1.1.1` November 12, 2019	November 12, 2019	9.82 Thousand
sub_string +9.8 Thousand Downloads	`1.2` November 12, 2019	November 12, 2019	9.8 Thousand
ruby_unicode_prop +6.32 Thousand Downloads	`1.0.2` November 12, 2019	November 12, 2019	6.32 Thousand