updating DIRECTORY.md

Author: github-actions

DIRECTORY.md

@@ -1,6 +1,8 @@
 
 ## Ciphers
-  * [Caesarcipher](https://github.com/TheAlgorithms/Go/blob/master/ciphers/CaesarCipher.go)
+  * Caesar
+    * [Caesar Test](https://github.com/TheAlgorithms/Go/blob/master/ciphers/caesar/caesar_test.go)
+    * [Caesarcipher](https://github.com/TheAlgorithms/Go/blob/master/ciphers/caesar/CaesarCipher.go)
   * [Diffiehellmankeyexchange](https://github.com/TheAlgorithms/Go/blob/master/ciphers/diffieHellmanKeyExchange.go)
   * [Rot13](https://github.com/TheAlgorithms/Go/blob/master/ciphers/Rot13.go)
   * Rsa