updating DIRECTORY.md

Author: github-actions

DIRECTORY.md

@@ -31,6 +31,7 @@
   * [DecimalToBinary](https://github.com/TheAlgorithms/Javascript/blob/master/Conversions/DecimalToBinary.js)
   * [DecimalToHex](https://github.com/TheAlgorithms/Javascript/blob/master/Conversions/DecimalToHex.js)
   * [DecimalToOctal](https://github.com/TheAlgorithms/Javascript/blob/master/Conversions/DecimalToOctal.js)
+  * [HexToDecimal](https://github.com/TheAlgorithms/Javascript/blob/master/Conversions/HexToDecimal.js)
   * [HexToRGB](https://github.com/TheAlgorithms/Javascript/blob/master/Conversions/HexToRGB.js)
   * [OctToDecimal](https://github.com/TheAlgorithms/Javascript/blob/master/Conversions/OctToDecimal.js)
   * [RgbHsvConversion](https://github.com/TheAlgorithms/Javascript/blob/master/Conversions/RgbHsvConversion.js)