fixed typo for README Faker::JapaneseMedia::CowboyBebop (#2863)

Faker::JapaneseMedia::CowboyBebop.songs => Faker::JapaneseMedia::CowboyBebop.song

Author: jacoyutorius

doc/japanese_media/cowboy_bebop.md

@@ -5,6 +5,6 @@ Available since version @faker.version next
 ```ruby
 Faker::JapaneseMedia::CowboyBebop.character #=> "Spike Spiegel"
 Faker::JapaneseMedia::CowboyBebop.episode #=> "Honky Tonk Women"
-Faker::JapaneseMedia::CowboyBebop.songs #=> "Live in Baghdad"
+Faker::JapaneseMedia::CowboyBebop.song #=> "Live in Baghdad"
 Faker::JapaneseMedia::CowboyBebop.quote #=> "Bang!"
 ```