fix(sprint-1): resolve TypeError by using let instead of const

Author: Tarawally

Sprint-1/2-mandatory-errors/1.js

@@ -1,4 +1,11 @@
 // trying to create an age variable and then reassign the value by 1
 
-const age = 33;
+// const age = 33;
+// age = age + 1;
+
+// TypeError: Assignment to constant variable - `const` cannot be reassigned
+// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/const
+
+// Solution:
+let age = 33;
 age = age + 1;