Add function to convert string to upper snake case

Author: mrafeie

Sprint-3/3-mandatory-implement/2-cases.js

@@ -14,3 +14,6 @@
 // You will need to come up with an appropriate name for the function
 // Use the MDN string documentation to help you find a solution
 // This might help https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/toUpperCase
+function toUpperSnakeCase(str) { 
+  return str.toUpperCase().replaceAll(" ", "_");
+}