updating DIRECTORY.md

Author: github-actions

DIRECTORY.md

@@ -168,6 +168,8 @@
  * [MaxCharacter](https://github.com/TheAlgorithms/Javascript/blob/master/String/MaxCharacter.test.js)
  * [PatternMatching](https://github.com/TheAlgorithms/Javascript/blob/master/String/PatternMatching.js)
  * [PatternMatching](https://github.com/TheAlgorithms/Javascript/blob/master/String/PatternMatching.test.js)
+ * [PermutateString](https://github.com/TheAlgorithms/Javascript/blob/master/String/PermutateString.js)
+ * [PermutateString](https://github.com/TheAlgorithms/Javascript/blob/master/String/PermutateString.test.js)
  * [ReverseString](https://github.com/TheAlgorithms/Javascript/blob/master/String/ReverseString.js)
  * [ReverseString](https://github.com/TheAlgorithms/Javascript/blob/master/String/ReverseString.test.js)
  * [ReverseWords](https://github.com/TheAlgorithms/Javascript/blob/master/String/ReverseWords.js)