Update app.py

app.py

@@ -16,7 +16,7 @@ def to_uppercase(arg1:str)-> str: #it's import to specify the return type
     output = ""
     for text in arg1:
         if i % 2 == 0:
-            text.upper()
+            text = text.upper()
         i += 1
         output = output + text
     return output