Updated the dependencies in README.md (#159)

Updated the dependencies in README.md and added one of the dependencies which is yarn, without which the make build command was failing

Author: hemanthsavasere

README.md

@@ -116,6 +116,7 @@ Stencil clients allows application to interact with stencil server to eserialize
 
     - Git
     - Go 1.16 or above
+    - Yarn (Needed for UI)
     - PostgreSQL 13 or above
 
 </details>